build: prevent global LIBS from influencing src and lib build targets

Currently, LIBS is already used through other macros.

acinclude.m4

@@ -130,7 +130,7 @@ int main (void)
     ]])
   ],[
     tst_lib_xnet_required="yes"
-    LIBS="$LIBS -lxnet"
+    LIBS="-lxnet $LIBS"
   ])
   AC_MSG_RESULT([$tst_lib_xnet_required])
 ])
@@ -2103,7 +2103,6 @@ AC_DEFUN([CURL_CHECK_LIBS_CLOCK_GETTIME_MONOTONIC], [
     #
     curl_cv_save_LIBS="$LIBS"
     curl_cv_gclk_LIBS="unknown"
-    curl_cv_save_CURL_LIBS="$CURL_LIBS"
     #
     for x_xlibs in '' '-lrt' '-lposix4' ; do
       if test "$curl_cv_gclk_LIBS" = "unknown"; then
@@ -2155,7 +2154,6 @@ AC_DEFUN([CURL_CHECK_LIBS_CLOCK_GETTIME_MONOTONIC], [
         else
           LIBS="$curl_cv_gclk_LIBS $curl_cv_save_LIBS"
         fi
-        CURL_LIBS="$CURL_LIBS $curl_cv_gclk_LIBS"
         AC_MSG_RESULT([$curl_cv_gclk_LIBS])
         ac_cv_func_clock_gettime="yes"
         ;;
@@ -2197,7 +2195,6 @@ AC_DEFUN([CURL_CHECK_LIBS_CLOCK_GETTIME_MONOTONIC], [
         AC_MSG_WARN([HAVE_CLOCK_GETTIME_MONOTONIC will not be defined])
         ac_cv_func_clock_gettime="no"
         LIBS="$curl_cv_save_LIBS"
-        CURL_LIBS="$curl_cv_save_CURL_LIBS"
       ])
     fi
     #

configure.ac

@@ -168,9 +168,10 @@ curl_verbose_msg="enabled (--disable-verbose)"
     init_ssl_msg=${curl_ssl_msg}
 
 dnl
-dnl Save anything in $LIBS for later
+dnl Save some initial values the user might have provided
 dnl
-ALL_LIBS=$LIBS
+INITIAL_LDFLAGS=$LDFLAGS
+INITIAL_LIBS=$LIBS
 
 dnl
 dnl Detect the canonical host and target build environment
@@ -682,6 +683,20 @@ dnl **********************************************************************
 dnl Checks for libraries.
 dnl **********************************************************************
 
+AC_MSG_CHECKING([whether to use libgcc])
+AC_ARG_ENABLE(libgcc,
+AC_HELP_STRING([--enable-libgcc],[use libgcc when linking]),
+[ case "$enableval" in
+  yes)
+       LIBS="-lgcc $LIBS"
+       AC_MSG_RESULT(yes)
+       ;;
+  *)   AC_MSG_RESULT(no)
+       ;;
+  esac ],
+       AC_MSG_RESULT(no)
+)
+
 CURL_CHECK_LIB_XNET
 
 dnl gethostbyname without lib or in the nsl lib?
@@ -690,7 +705,7 @@ AC_CHECK_FUNC(gethostbyname,
               ],
               [ AC_CHECK_LIB(nsl, gethostbyname,
                              [HAVE_GETHOSTBYNAME="1"
-                             LIBS="$LIBS -lnsl"
+                             LIBS="-lnsl $LIBS"
                              ])
               ])
 
@@ -699,7 +714,7 @@ then
   dnl gethostbyname in the socket lib?
   AC_CHECK_LIB(socket, gethostbyname,
                [HAVE_GETHOSTBYNAME="1"
-               LIBS="$LIBS -lsocket"
+               LIBS="-lsocket $LIBS"
                ])
 fi
 
@@ -710,7 +725,7 @@ then
                [HAVE_GETHOSTBYNAME="1"
                CPPFLAGS="-I/dev/env/WATT_ROOT/inc"
                LDFLAGS="-L/dev/env/WATT_ROOT/lib"
-               LIBS="$LIBS -lwatt"
+               LIBS="-lwatt $LIBS"
                ])
 fi
 
@@ -754,7 +769,7 @@ then
     fi
     if test ! -z "$winsock_LIB"; then
       my_ac_save_LIBS=$LIBS
-      LIBS="$LIBS $winsock_LIB"
+      LIBS="$winsock_LIB $LIBS"
       AC_MSG_CHECKING([for gethostbyname in $winsock_LIB])
       AC_LINK_IFELSE([
         AC_LANG_PROGRAM([[
@@ -829,7 +844,7 @@ then
   dnl gethostbyname in the network lib - for Haiku OS
   AC_CHECK_LIB(network, gethostbyname,
                [HAVE_GETHOSTBYNAME="1"
-               LIBS="$LIBS -lnetwork"
+               LIBS="-lnetwork $LIBS"
                ])
 fi
 
@@ -838,7 +853,7 @@ then
   dnl gethostbyname in the net lib - for BeOS
   AC_CHECK_LIB(net, gethostbyname,
                [HAVE_GETHOSTBYNAME="1"
-               LIBS="$LIBS -lnet"
+               LIBS="-lnet $LIBS"
                ])
 fi
 
@@ -877,19 +892,101 @@ dnl **********************************************************************
 CURL_NETWORK_AND_TIME_LIBS=$LIBS
 
 dnl **********************************************************************
-AC_MSG_CHECKING([whether to use libgcc])
-AC_ARG_ENABLE(libgcc,
-AC_HELP_STRING([--enable-libgcc],[use libgcc when linking]),
-[ case "$enableval" in
-  yes)
-        ALL_LIBS="$ALL_LIBS -lgcc"
-       AC_MSG_RESULT(yes)
-       ;;
-  *)   AC_MSG_RESULT(no)
-       ;;
-  esac ],
-       AC_MSG_RESULT(no)
-)
+dnl Check for the presence of ZLIB libraries and headers
+dnl **********************************************************************
+
+dnl Check for & handle argument to --with-zlib.
+
+clean_CPPFLAGS=$CPPFLAGS
+clean_LDFLAGS=$LDFLAGS
+clean_LIBS=$LIBS
+ZLIB_LIBS=""
+AC_ARG_WITH(zlib,
+AC_HELP_STRING([--with-zlib=PATH],[search for zlib in PATH])
+AC_HELP_STRING([--without-zlib],[disable use of zlib]),
+               [OPT_ZLIB="$withval"])
+
+if test "$OPT_ZLIB" = "no" ; then
+    AC_MSG_WARN([zlib disabled])
+else
+  if test "$OPT_ZLIB" = "yes" ; then
+    OPT_ZLIB=""
+  fi
+
+  if test -z "$OPT_ZLIB" ; then
+    dnl check for the lib first without setting any new path, since many
+    dnl people have it in the default path
+
+    AC_CHECK_LIB(z, inflateEnd,
+                   dnl libz found, set the variable
+                   [HAVE_LIBZ="1"
+                    LIBS="-lz $LIBS"],
+                   dnl if no lib found, try /usr/local
+                   [OPT_ZLIB="/usr/local"])
+
+  fi
+
+  dnl Add a nonempty path to the compiler flags
+  if test -n "$OPT_ZLIB"; then
+     CPPFLAGS="$CPPFLAGS -I$OPT_ZLIB/include"
+     LDFLAGS="$LDFLAGS -L$OPT_ZLIB/lib$libsuff"
+  fi
+
+  AC_CHECK_HEADER(zlib.h,
+    [
+    dnl zlib.h was found
+    HAVE_ZLIB_H="1"
+    dnl if the lib wasn't found already, try again with the new paths
+    if test "$HAVE_LIBZ" != "1"; then
+      AC_CHECK_LIB(z, gzread,
+                   [
+                   dnl the lib was found!
+                   HAVE_LIBZ="1"
+                   LIBS="-lz $LIBS"
+                   ],
+                   [ CPPFLAGS=$clean_CPPFLAGS
+                   LDFLAGS=$clean_LDFLAGS])
+    fi
+    ],
+    [
+      dnl zlib.h was not found, restore the flags
+      CPPFLAGS=$clean_CPPFLAGS
+      LDFLAGS=$clean_LDFLAGS]
+    )
+
+  if test "$HAVE_LIBZ" = "1" && test "$HAVE_ZLIB_H" != "1"
+  then
+    AC_MSG_WARN([configure found only the libz lib, not the header file!])
+    HAVE_LIBZ=""
+    CPPFLAGS=$clean_CPPFLAGS
+    LDFLAGS=$clean_LDFLAGS
+    LIBS=$clean_LIBS
+  elif test "$HAVE_LIBZ" != "1" && test "$HAVE_ZLIB_H" = "1"
+  then
+    AC_MSG_WARN([configure found only the libz header file, not the lib!])
+    CPPFLAGS=$clean_CPPFLAGS
+    LDFLAGS=$clean_LDFLAGS
+    LIBS=$clean_LIBS
+  elif test "$HAVE_LIBZ" = "1" && test "$HAVE_ZLIB_H" = "1"
+  then
+    dnl both header and lib were found!
+    AC_SUBST(HAVE_LIBZ)
+    AC_DEFINE(HAVE_ZLIB_H, 1, [if you have the zlib.h header file])
+    AC_DEFINE(HAVE_LIBZ, 1, [if zlib is available])
+
+    ZLIB_LIBS="-lz"
+    LIBS="-lz $clean_LIBS"
+
+    dnl replace 'HAVE_LIBZ' in the automake makefile.ams
+    AMFIXLIB="1"
+    AC_MSG_NOTICE([found both libz and libz.h header])
+    curl_zlib_msg="enabled"
+  fi
+fi
+
+dnl set variable for use in automakefile(s)
+AM_CONDITIONAL(HAVE_LIBZ, test x"$AMFIXLIB" = x1)
+AC_SUBST(ZLIB_LIBS)
 
 dnl **********************************************************************
 dnl Check for LDAP
@@ -1315,29 +1412,29 @@ if test x"$want_gss" = xyes; then
   if test -n "$gnu_gss"; then
     curl_gss_msg="enabled (GNU GSS)"
     LDFLAGS="$LDFLAGS $GSSAPI_LIB_DIR"
-    LIBS="$LIBS -lgss"
+    LIBS="-lgss $LIBS"
   elif test -z "$GSSAPI_LIB_DIR"; then
      case $host in
      *-*-darwin*)
-        LIBS="$LIBS -lgssapi_krb5 -lresolv"
+        LIBS="-lgssapi_krb5 -lresolv $LIBS"
         ;;
      *)
         if test -f "$GSSAPI_ROOT/bin/krb5-config"; then
            dnl krb5-config doesn't have --libs-only-L or similar, put everything
            dnl into LIBS
            gss_libs=`$GSSAPI_ROOT/bin/krb5-config --libs gssapi`
-           LIBS="$LIBS $gss_libs"
+           LIBS="$gss_libs $LIBS"
         elif test "$GSSAPI_ROOT" != "yes"; then
            LDFLAGS="$LDFLAGS -L$GSSAPI_ROOT/lib$libsuff"
-           LIBS="$LIBS -lgssapi"
+           LIBS="-lgssapi $LIBS"
         else
-           LIBS="$LIBS -lgssapi"
+           LIBS="-lgssapi $LIBS"
         fi
         ;;
      esac
   else
      LDFLAGS="$LDFLAGS $GSSAPI_LIB_DIR"
-     LIBS="$LIBS -lgssapi"
+     LIBS="-lgssapi $LIBS"
   fi
 else
   CPPFLAGS="$save_CPPFLAGS"
@@ -1484,7 +1581,7 @@ if test "$curl_ssl_msg" = "$init_ssl_msg" && test X"$OPT_SSL" != Xno; then
       dnl the argument to --with-ssl we don't know what
       dnl additional libs may be necessary.  Hope that we
       dnl don't need any.
-      LIBS="$LIBS $SSL_LIBS"
+      LIBS="$SSL_LIBS $LIBS"
     fi
   fi
 
@@ -1536,7 +1633,7 @@ if test "$curl_ssl_msg" = "$init_ssl_msg" && test X"$OPT_SSL" != Xno; then
         dnl we didn't find the SSL lib, try the RSAglue/rsaref stuff
         AC_MSG_CHECKING(for ssl with RSAglue/rsaref libs in use);
         OLIBS=$LIBS
-        LIBS="$LIBS -lRSAglue -lrsaref"
+        LIBS="-lRSAglue -lrsaref $LIBS"
         AC_CHECK_LIB(ssl, SSL_connect)
         if test "$ac_cv_lib_ssl_SSL_connect" != yes; then
             dnl still no SSL_connect
@@ -1651,92 +1748,6 @@ if test "$curl_ssl_msg" = "$init_ssl_msg" && test X"$OPT_SSL" != Xno; then
 
 fi
 
-dnl **********************************************************************
-dnl Check for the presence of ZLIB libraries and headers
-dnl **********************************************************************
-
-dnl Check for & handle argument to --with-zlib.
-
-_cppflags=$CPPFLAGS
-_ldflags=$LDFLAGS
-AC_ARG_WITH(zlib,
-AC_HELP_STRING([--with-zlib=PATH],[search for zlib in PATH])
-AC_HELP_STRING([--without-zlib],[disable use of zlib]),
-               [OPT_ZLIB="$withval"])
-
-if test "$OPT_ZLIB" = "no" ; then
-    AC_MSG_WARN([zlib disabled])
-else
-  if test "$OPT_ZLIB" = "yes" ; then
-     OPT_ZLIB=""
-  fi
-
-  if test -z "$OPT_ZLIB" ; then
-    dnl check for the lib first without setting any new path, since many
-    dnl people have it in the default path
-
-    AC_CHECK_LIB(z, inflateEnd,
-                   dnl libz found, set the variable
-                   [HAVE_LIBZ="1"],
-                   dnl if no lib found, try /usr/local
-                   [OPT_ZLIB="/usr/local"])
-
-  fi
-
-  dnl Add a nonempty path to the compiler flags
-  if test -n "$OPT_ZLIB"; then
-     CPPFLAGS="$CPPFLAGS -I$OPT_ZLIB/include"
-     LDFLAGS="$LDFLAGS -L$OPT_ZLIB/lib$libsuff"
-  fi
-
-  AC_CHECK_HEADER(zlib.h,
-    [
-    dnl zlib.h was found
-    HAVE_ZLIB_H="1"
-    dnl if the lib wasn't found already, try again with the new paths
-    if test "$HAVE_LIBZ" != "1"; then
-      AC_CHECK_LIB(z, gzread,
-                   [
-                   dnl the lib was found!
-                   HAVE_LIBZ="1"
-                   ],
-                   [ CPPFLAGS=$_cppflags
-                   LDFLAGS=$_ldflags])
-    fi
-    ],
-    [
-      dnl zlib.h was not found, restore the flags
-      CPPFLAGS=$_cppflags
-      LDFLAGS=$_ldflags]
-    )
-
-  if test "$HAVE_LIBZ" = "1" && test "$HAVE_ZLIB_H" != "1"
-  then
-    AC_MSG_WARN([configure found only the libz lib, not the header file!])
-    HAVE_LIBZ=""
-  elif test "$HAVE_LIBZ" != "1" && test "$HAVE_ZLIB_H" = "1"
-  then
-    AC_MSG_WARN([configure found only the libz header file, not the lib!])
-  elif test "$HAVE_LIBZ" = "1" && test "$HAVE_ZLIB_H" = "1"
-  then
-    dnl both header and lib were found!
-    AC_SUBST(HAVE_LIBZ)
-    AC_DEFINE(HAVE_ZLIB_H, 1, [if you have the zlib.h header file])
-    AC_DEFINE(HAVE_LIBZ, 1, [if zlib is available])
-
-    CURL_LIBS="$CURL_LIBS -lz"
-    LIBS="$LIBS -lz"
-
-    dnl replace 'HAVE_LIBZ' in the automake makefile.ams
-    AMFIXLIB="1"
-    AC_MSG_NOTICE([found both libz and libz.h header])
-    curl_zlib_msg="enabled"
-  fi
-fi
-
-dnl set variable for use in automakefile(s)
-AM_CONDITIONAL(HAVE_LIBZ, test x"$AMFIXLIB" = x1)
-
 dnl **********************************************************************
 dnl Check for the random seed preferences
 dnl **********************************************************************
@@ -1853,7 +1864,7 @@ if test "$curl_ssl_msg" = "$init_ssl_msg"; then
       CLEANCPPFLAGS="$CPPFLAGS"
       CLEADLDFLAGS="$LDFLAGS"
 
-      LIBS="$LIBS $addlib"
+      LIBS="$addlib $LIBS"
       LDFLAGS="$LDFLAGS $addld"
       if test "$addcflags" != "-I/usr/include"; then
          CPPFLAGS="$CPPFLAGS $addcflags"
@@ -1918,9 +1929,9 @@ if test "$GNUTLS_ENABLED" = "1"; then
   if test "$USE_GNUTLS_NETTLE" = "1"; then
     AC_DEFINE(USE_GNUTLS_NETTLE, 1, [if GnuTLS uses nettle as crypto backend])
     AC_SUBST(USE_GNUTLS_NETTLE, [1])
-    LIBS="$LIBS -lnettle"
+    LIBS="-lnettle $LIBS"
   else
-    LIBS="$LIBS -lgcrypt"
+    LIBS="-lgcrypt $LIBS"
   fi
 fi
 
@@ -1999,8 +2010,7 @@ if test "$curl_ssl_msg" = "$init_ssl_msg"; then
     if test "x$USE_POLARSSL" = "xyes"; then
       AC_MSG_NOTICE([detected PolarSSL])
 
-      CURL_LIBS="$CURL_LIBS -lpolarssl"
-      LIBS="$LIBS -lpolarssl"
+      LIBS="-lpolarssl $LIBS"
 
       if test -n "$polarssllib"; then
         dnl when shared libs were found in a path that the run-time
@@ -2083,8 +2093,7 @@ if test "$curl_ssl_msg" = "$init_ssl_msg"; then
     if test "x$USE_CYASSL" = "xyes"; then
       AC_MSG_NOTICE([detected CyaSSL])
 
-      CURL_LIBS="$CURL_LIBS -lcyassl -lm"
-      LIBS="$LIBS -lcyassl -lm"
+      LIBS="-lcyassl -lm $LIBS"
 
       if test -n "$cyassllib"; then
         dnl when shared libs were found in a path that the run-time
@@ -2156,7 +2165,7 @@ if test "$curl_ssl_msg" = "$init_ssl_msg"; then
       CLEANLIBS="$LIBS"
       CLEANCPPFLAGS="$CPPFLAGS"
 
-      LIBS="$LIBS $addlib"
+      LIBS="$addlib $LIBS"
       if test "$addcflags" != "-I/usr/include"; then
          CPPFLAGS="$CPPFLAGS $addcflags"
       fi
@@ -2410,7 +2419,7 @@ if test X"$OPT_LIBSSH2" != Xno; then
 
   LDFLAGS="$LDFLAGS $LD_SSH2"
   CPPFLAGS="$CPPFLAGS $CPP_SSH2"
-  LIBS="$LIBS $LIB_SSH2"
+  LIBS="$LIB_SSH2 $LIBS"
 
   AC_CHECK_LIB(ssh2, libssh2_channel_open_ex)
 
@@ -2506,7 +2515,7 @@ if test X"$OPT_LIBRTMP" != Xno; then
 
   LDFLAGS="$LDFLAGS $LD_RTMP"
   CPPFLAGS="$CPPFLAGS $CPP_RTMP"
-  LIBS="$LIBS $LIB_RTMP"
+  LIBS="$LIB_RTMP $LIBS"
 
   AC_CHECK_LIB(rtmp, RTMP_Init,
     [
@@ -3329,16 +3338,13 @@ fi
 
 dnl
 dnl All the library dependencies put into $LIB apply to libcurl only.
-dnl Those in $CURL_LIBS apply to the curl command-line client only.
-dnl Those in $ALL_LIBS apply to all targets, including test targets.
 dnl
 LIBCURL_LIBS=$LIBS
 
 AC_SUBST(LIBCURL_LIBS)
-AC_SUBST(CURL_LIBS)
 AC_SUBST(CURL_NETWORK_LIBS)
 AC_SUBST(CURL_NETWORK_AND_TIME_LIBS)
-LIBS=$ALL_LIBS  dnl LIBS is a magic variable that's used for every link
+dnl LIBS is a magic variable that's used for every link
 
 dnl BLANK_AT_MAKETIME might be used in some of our Makefile.am files to
 dnl blank LIBS variable used in generated makefile at makefile processing
@@ -3478,7 +3484,6 @@ squeeze DEFS
 squeeze LDFLAGS
 squeeze LIBS
 
-squeeze CURL_LIBS
 squeeze LIBCURL_LIBS
 squeeze CURL_NETWORK_LIBS
 squeeze CURL_NETWORK_AND_TIME_LIBS

curl-config.in

@@ -148,14 +148,14 @@ while test $# -gt 0; do
 	   CURLLIBDIR=""
 	fi
 	if test "X@REQUIRE_LIB_DEPS@" = "Xyes"; then
-	  echo ${CURLLIBDIR}-lcurl @LIBCURL_LIBS@ @LIBS@
+	  echo ${CURLLIBDIR}-lcurl @LIBCURL_LIBS@
 	else
-	  echo ${CURLLIBDIR}-lcurl @LIBS@
+	  echo ${CURLLIBDIR}-lcurl
 	fi
 	;;
 
     --static-libs)
-	echo @libdir@/libcurl.@libext@ @LDFLAGS@ @LIBCURL_LIBS@ @LIBS@
+	echo @libdir@/libcurl.@libext@ @LDFLAGS@ @LIBCURL_LIBS@
 	;;
 
     --configure)

lib/Makefile.am

@@ -132,6 +132,9 @@ if VERSIONED_SYMBOLS
 VERSIONED_SYMBOLS = -Wl,--version-script=libcurl.vers
 endif
 
+# Prevent global LIBS from influencing lib build targets
+LIBS = $(BLANK_AT_MAKETIME)
+
 libcurl_la_LDFLAGS = $(UNDEF) $(VERSIONINFO) $(MIMPURE) $(VERSIONED_SYMBOLS) $(LIBCURL_LIBS)
 
 if DOING_CURL_SYMBOL_HIDING

libcurl.pc.in

@@ -34,6 +34,6 @@ Name: libcurl
 URL: http://curl.haxx.se/
 Description: Library to transfer files with ftp, http, etc.
 Version: @CURLVERSION@
-Libs: -L${libdir} -lcurl @LIBS@
-Libs.private: @LIBCURL_LIBS@ @LIBS@
+Libs: -L${libdir} -lcurl
+Libs.private: @LIBCURL_LIBS@
 Cflags: -I${includedir} @CPPFLAG_CURL_STATICLIB@

src/Makefile.am

@@ -54,7 +54,15 @@ include Makefile.inc
 # This might hold -Werror
 CFLAGS += @CURL_CFLAG_EXTRAS@ @LIBMETALINK_CFLAGS@
 
-curl_LDADD = $(top_builddir)/lib/libcurl.la @CURL_LIBS@ @LIBMETALINK_LIBS@
+# Prevent global LIBS from influencing src build targets
+LIBS = $(BLANK_AT_MAKETIME)
+
+if USE_EXPLICIT_LIB_DEPS
+curl_LDADD = $(top_builddir)/lib/libcurl.la @LIBMETALINK_LIBS@ @LIBCURL_LIBS@
+else
+curl_LDADD = $(top_builddir)/lib/libcurl.la @LIBMETALINK_LIBS@ @ZLIB_LIBS@ @CURL_NETWORK_AND_TIME_LIBS@
+endif
+
 curl_LDFLAGS = @LIBMETALINK_LDFLAGS@
 curl_DEPENDENCIES = $(top_builddir)/lib/libcurl.la
 BUILT_SOURCES = hugehelp.c