Allow setting PCRE_{CFLAGS,LIBS} when building SWIG with PCRE.

These options can be used to override the values returned by pcre-config, e.g.
to build using a static PCRE library even if pcre-config prefers to use the
shared one by default.

Use the updated AX_PATH_GENERIC macro from autoconf archive which was fixed to
allow the options set by the user to override the ones returned by pcre-config
(in fact, pcre-config isn't even called at all if these options are set).

git-svn-id: https://swig.svn.sourceforge.net/svnroot/swig/trunk@12548 626c5289-ae23-0410-ae9c-e8d60b6d4f22

CHANGES.current

@@ -5,6 +5,10 @@ See the RELEASENOTES file for a summary of changes in each release.
 Version 2.0.3 (in progress)
 ===========================
 
+2011-03-21: vadz
+	    [build] Allow setting PCRE_CFLAGS and PCRE_LIBS to override the values returned by
+	    pcre-config, e.g. to allow using a static version of PCRE library.
+
 2011-03-17: wsfulton
 	    [UTL] Add missing headers in generated STL wrappers to fix compilation with gcc-4.6.
 

README

@@ -57,8 +57,12 @@ You must use GNU `make' to build SWIG.
 
 http://www.gnu.org/software/make/
 
-PCRE needs to be installed on your system to build SWIG. The configure
+PCRE needs to be installed on your system to build SWIG, in particular
-script will provide instructions for obtaining PCRE if it cannot be found.
+pcre-config must be available. If you have PCRE headers and libraries but not
+pcre-config itself or, alternatively, wish to override the compiler or linker
+flags returned by pcre-config, you may set PCRE_LIBS and PCRE_CFLAGS variables
+to be used instead. And if you don't have PCRE at all, the configure script
+will provide instructions for obtaining it.
 
 To build and install SWIG, simply type the following:
 

Tools/config/ax_path_generic.m4

@@ -9,7 +9,7 @@
 # DESCRIPTION
 #
 #   Runs the LIBRARY-config script and defines LIBRARY_CFLAGS and
-#   LIBRARY_LIBS
+#   LIBRARY_LIBS unless the user had predefined them in the environment.
 #
 #   The script must support `--cflags' and `--libs' args. If MINIMUM-VERSION
 #   is specified, the script must also support the `--version' arg. If the
@@ -22,6 +22,12 @@
 #   to extract the version number. Use it if your 'foo-config --version'
 #   dumps something like 'Foo library v1.0.0 (alfa)' instead of '1.0.0'.
 #
+#   The macro respects LIBRARY_CONFIG, LIBRARY_CFLAGS and LIBRARY_LIBS
+#   variables. If the first one is defined, it specifies the name of the
+#   config script to use. If the latter two are defined, the script is not
+#   ran at all and their values are used instead (if only one of them is
+#   defined, the empty value of the remaining one is still used).
+#
 #   Example:
 #
 #     AX_PATH_GENERIC(Foo, 1.0.0)
@@ -44,6 +50,14 @@
 #     BAR_CFLAGS to `bar-config --cflags`
 #     BAR_LIBS   to `bar-config --libs`
 #
+#   Example:
+#
+#     ./configure BAZ_LIBS=/usr/lib/libbaz.a
+#
+#   would link with a static version of baz library even if `baz-config
+#   --libs` returns just "-lbaz" that would normally result in using the
+#   shared library.
+#
 #   This macro is a rearranged version of AC_PATH_GENERIC from Angus Lees.
 #
 # LICENSE
@@ -55,7 +69,7 @@
 #   and this notice are preserved. This file is offered as-is, without any
 #   warranty.
 
-#serial 10
+#serial 11
 
 AU_ALIAS([AC_PATH_GENERIC], [AX_PATH_GENERIC])
 AC_DEFUN([AX_PATH_GENERIC],[
@@ -75,6 +89,13 @@ AC_DEFUN([AX_PATH_GENERIC],[
   AC_ARG_VAR(UP[]_CFLAGS, [CFLAGS used for $1])
   AC_ARG_VAR(UP[]_LIBS,   [LIBS used for $1])
 
+  AS_IF([test x$UP[]_CFLAGS != x -o x$UP[]_LIBS != x],[
+    dnl Don't run config script at all, use user-provided values instead.
+    AC_SUBST(UP[]_CFLAGS)
+    AC_SUBST(UP[]_LIBS)
+    :
+    $4
+  ],[
     AS_IF([test x$DOWN[]_config_exec_prefix != x],[
       DOWN[]_config_args="$DOWN[]_config_args --exec-prefix=$DOWN[]_config_exec_prefix"
       AS_IF([test x${UP[]_CONFIG+set} != xset],[
@@ -136,6 +157,7 @@ AC_DEFUN([AX_PATH_GENERIC],[
 	$4
       ])
     ])
+  ])
 
   popdef([UP])
   popdef([DOWN])