bump version requirement for MHD to 0.9.63

ChangeLog

@@ -1,3 +1,7 @@
+Sat 27 Apr 2019 06:36:31 AM CEST
+  Bump libmicrohttpd version requirement as some intermediate
+  versions have relevant bugs that cause problems. -CG
+
 Sat Apr 27 01:50:43 2019 +0200
   RECLAIM: No longer experimental
 

README

@@ -69,7 +69,7 @@ These are the direct dependencies for running GNUnet:
   * libidn2 (prefered)
   or
   * libidn           >= 1.0
-- libmicrohttpd      >= 0.9.52      (strongly recommended for
+- libmicrohttpd      >= 0.9.63      (strongly recommended for
                                      a wide range of features)
 - makeinfo           >= 4.8
 - make[*3]

configure.ac

@@ -1297,12 +1297,12 @@ AC_ARG_WITH(microhttpd,
         AC_CHECK_HEADERS([microhttpd.h],
 	  AC_CHECK_DECL(MHD_OPTION_PER_IP_CONNECTION_LIMIT,
             AC_CHECK_LIB([microhttpd], [MHD_get_fdset2],
-              [AC_MSG_CHECKING([for libmicrohttpd >= 0.9.52])
+              [AC_MSG_CHECKING([for libmicrohttpd >= 0.9.63])
               AC_COMPILE_IFELSE([AC_LANG_SOURCE([
                 #include "$native_srcdir/src/include/platform.h"
                 #include <microhttpd.h>
-                #if (MHD_VERSION < 0x0094200)
-                #error needs at least version 0.9.42
+                #if (MHD_VERSION < 0x0096300)
+                #error needs at least version 0.9.63
                 #endif
                 int main () { return 0; }
                ])],

doc/handbook/chapters/installation.texi

@@ -38,7 +38,7 @@ The mandatory libraries and applications are
 @item libgcrypt 1.6 or above
 @item libextractor
 @item libidn2 or libidn
-@item libmicrohttpd 0.9.52 or above
+@item libmicrohttpd 0.9.63 or above
 @item libunistring
 @item libgmp
 @item libgnurl or libcurl (libcurl has to be linked to GnuTLS) 7.35.0 or above