[PATCH v2 util-macros] Add XORG_WITH_PERL macro

[Gaetan Nadon]

Following the same pattern as XMLTO and friends.
Allows all modules to use the same interface, variables
and options to check for perl.
Perl is used in libX11 and xserver.

Signed-off-by: Gaetan Nadon <memsize at videotron.ca>
---
 xorg-macros.m4.in |   56 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 56 insertions(+), 0 deletions(-)

diff --git a/xorg-macros.m4.in b/xorg-macros.m4.in
index d3b0b7e..e8c14c3 100644
--- a/xorg-macros.m4.in
+++ b/xorg-macros.m4.in
@@ -494,6 +494,62 @@ m4_ifval([$1],[AC_MSG_WARN(Checking for MIN-VERSION is not implemented.)])
 AM_CONDITIONAL([HAVE_XSLTPROC], [test "$have_xsltproc" = yes])
 ]) # XORG_WITH_XSLTPROC
 
+# XORG_WITH_PERL([MIN-VERSION], [DEFAULT])
+# ----------------------------------------
+# Minimum version: 1.15.0
+#
+# PERL (Practical Extraction and Report Language) is a language optimized for
+# scanning arbitrary text files, extracting information from those text files,
+# and printing reports based on that information.
+#
+# When DEFAULT is not specified, --with-perl assumes 'auto'.
+#
+# Interface to module:
+# HAVE_PERL: used in makefiles to conditionally scan text files
+# PERL:	     returns the path of the perl program found
+#	     returns the path set by the user in the environment
+# --with-perl: 'yes' user instructs the module to use perl
+#	       'no' user instructs the module not to use perl
+# have_perl: returns yes if perl found in PATH or no
+#
+# If the user sets the value of PERL, AC_PATH_PROG skips testing the path.
+#
+AC_DEFUN([XORG_WITH_PERL],[
+AC_ARG_VAR([PERL], [Path to perl command])
+# Preserves the interface, should it be implemented later
+m4_ifval([$1], [m4_warn([syntax], [Checking for perl MIN-VERSION is not implemented])])
+m4_define([_defopt], m4_default([$2], [auto]))
+AC_ARG_WITH(perl,
+	AS_HELP_STRING([--with-perl],
+	   [Use perl for extracting information from files (default: ]_defopt[)]),
+	   [use_perl=$withval], [use_perl=]_defopt)
+m4_undefine([_defopt])
+
+if test "x$use_perl" = x"auto"; then
+   AC_PATH_PROG([PERL], [perl])
+   if test "x$PERL" = "x"; then
+        AC_MSG_WARN([perl not found - cannot extract information and report])
+	have_perl=no
+   else
+        have_perl=yes
+   fi
+elif test "x$use_perl" = x"yes" ; then
+   AC_PATH_PROG([PERL], [perl])
+   if test "x$PERL" = "x"; then
+        AC_MSG_ERROR([--with-perl=yes specified but perl not found in PATH])
+   fi
+   have_perl=yes
+elif test "x$use_perl" = x"no" ; then
+   if test "x$PERL" != "x"; then
+      AC_MSG_WARN([ignoring PERL environment variable since --with-perl=no was specified])
+   fi
+   have_perl=no
+else
+   AC_MSG_ERROR([--with-perl expects 'yes' or 'no'])
+fi
+
+AM_CONDITIONAL([HAVE_PERL], [test "$have_perl" = yes])
+]) # XORG_WITH_PERL
 
 # XORG_WITH_ASCIIDOC([MIN-VERSION], [DEFAULT])
 # ----------------
-- 
1.7.4.1