system.h: fix for MCST lcc compiler

Fixed build by MCST lcc compiler on MCST Elbrus 2000 architecture and do
some code cleanup.

e2k (Elbrus 2000) - this is VLIW/EPIC architecture, like Intel Itanium
architecture.

Ref: https://en.wikipedia.org/wiki/Elbrus_2000

Closes https://github.com/curl/curl/pull/4576

include/curl/system.h

@@ -137,15 +137,26 @@
 #  define CURL_TYPEOF_CURL_SOCKLEN_T int
 
 #elif defined(__LCC__)
-#  define CURL_TYPEOF_CURL_OFF_T     long
-#  define CURL_FORMAT_CURL_OFF_T     "ld"
-#  define CURL_FORMAT_CURL_OFF_TU    "lu"
-#  define CURL_SUFFIX_CURL_OFF_T     L
-#  define CURL_SUFFIX_CURL_OFF_TU    UL
-#  define CURL_TYPEOF_CURL_SOCKLEN_T int
+#  if defined(__e2k__) /* MCST eLbrus C Compiler */
+#    define CURL_TYPEOF_CURL_OFF_T     long
+#    define CURL_FORMAT_CURL_OFF_T     "ld"
+#    define CURL_FORMAT_CURL_OFF_TU    "lu"
+#    define CURL_SUFFIX_CURL_OFF_T     L
+#    define CURL_SUFFIX_CURL_OFF_TU    UL
+#    define CURL_TYPEOF_CURL_SOCKLEN_T socklen_t
+#    define CURL_PULL_SYS_TYPES_H      1
+#    define CURL_PULL_SYS_SOCKET_H     1
+#  else                /* Local (or Little) C Compiler */
+#    define CURL_TYPEOF_CURL_OFF_T     long
+#    define CURL_FORMAT_CURL_OFF_T     "ld"
+#    define CURL_FORMAT_CURL_OFF_TU    "lu"
+#    define CURL_SUFFIX_CURL_OFF_T     L
+#    define CURL_SUFFIX_CURL_OFF_TU    UL
+#    define CURL_TYPEOF_CURL_SOCKLEN_T int
+#  endif
 
 #elif defined(__SYMBIAN32__)
-#  if defined(__EABI__)  /* Treat all ARM compilers equally */
+#  if defined(__EABI__) /* Treat all ARM compilers equally */
 #    define CURL_TYPEOF_CURL_OFF_T     long long
 #    define CURL_FORMAT_CURL_OFF_T     "lld"
 #    define CURL_FORMAT_CURL_OFF_TU    "llu"
@@ -288,7 +299,6 @@
 #  define CURL_TYPEOF_CURL_SOCKLEN_T int
 
 #elif defined(__TINYC__) /* also known as tcc */
-
 #  define CURL_TYPEOF_CURL_OFF_T     long long
 #  define CURL_FORMAT_CURL_OFF_T     "lld"
 #  define CURL_FORMAT_CURL_OFF_TU    "llu"
@@ -377,6 +387,7 @@
 #    define CURL_SUFFIX_CURL_OFF_TU    ULL
 #  elif defined(__LP64__) || \
         defined(__x86_64__) || defined(__ppc64__) || defined(__sparc64__) || \
+        defined(__e2k__) || \
         (defined(__SIZEOF_LONG__) && __SIZEOF_LONG__ == 8) || \
         (defined(__LONG_MAX__) && __LONG_MAX__ == 9223372036854775807L)
 #    define CURL_TYPEOF_CURL_OFF_T     long