Fix nits and add note to UPGRADING.INTERNALS

Author: petk

UPGRADING.INTERNALS

@@ -183,6 +183,9 @@ PHP 8.4 INTERNALS UPGRADE NOTES
      used instead of the pkg-config search.
    - Added pkg-config support to find unixODBC and iODBC for the pdo_odbc
      extension.
+   - Added pkg-config support to find GNU MP library. As a fallback default
+     system paths are searched. When a directory argument is provided
+     (--with-gmp=DIR), it will be used instead of the pkg-config.
    - Removed BC enable_pear variable check due to --enable-pear configure option
      once used (use with_pear variable name).
    - Cache variables synced to php_cv_* naming scheme. If you use them for

ext/gmp/config.m4

@@ -1,9 +1,9 @@
 PHP_ARG_WITH([gmp],
   [for GNU MP support],
   [AS_HELP_STRING([[--with-gmp[=DIR]]],
-    [Include GNU MP support. Optional DIR is the library installation directory.
-    Also, the GMP_CFLAGS and GMP_LIBS environment variables can be used instead
-    of the DIR argument to customize the GMP paths.])])
+    [Include GNU MP support. Use PKG_CONFIG_PATH (or GMP_CFLAGS and GMP_LIBS)
+    environment variables, or alternatively the optional DIR argument to
+    customize where to look for the GNU MP library.])])
 
 if test "$PHP_GMP" != "no"; then
   gmp_found=no
@@ -20,14 +20,13 @@ if test "$PHP_GMP" != "no"; then
   LIBS_SAVED=$LIBS
   CFLAGS="$CFLAGS $GMP_CFLAGS"
   LIBS="$LIBS $GMP_LIBS"
-  gmp_check=
-  AC_CHECK_HEADER([gmp.h], [AC_CHECK_FUNC([__gmpz_rootrem], [gmp_check=ok])])
+  gmp_check=no
+  AC_CHECK_HEADER([gmp.h], [AC_CHECK_FUNC([__gmpz_rootrem], [gmp_check=yes])])
   CFLAGS=$CFLAGS_SAVED
   LIBS=$LIBS_SAVED
 
-  AS_VAR_IF([gmp_check], [ok],, [AC_MSG_ERROR([
-    GNU MP library check failed. GNU MP Library version 4.2 or greater required.
-    Please, check config.log for details.
+  AS_VAR_IF([gmp_check], [no], [AC_MSG_FAILURE([
+    The required GNU MP library version 4.2 or greater not found.
   ])])
 
   PHP_EVAL_LIBLINE([$GMP_LIBS], [GMP_SHARED_LIBADD])