[smuxi: 15/37] m4: allow pkg-config find mono in macOS

[Mirco M. M. Bauer <mmmbauer src gnome org>]

commit ea02c16abde4af5808fef2fe6bb445d7184a6038
Author: Andres G. Aragoneses <knocte gmail com>
Date:   Mon Feb 17 21:41:43 2020 +0800

    m4: allow pkg-config find mono in macOS
    
    Fixes this error:
    
    checking for mono >= 2.8... no
    configure: error: Package requirements (mono >= 2.8) were not met:
    
    No package 'mono' found
    
    Consider adjusting the PKG_CONFIG_PATH environment variable if you
    installed software in a non-standard prefix.
    
    Alternatively, you may set the environment variables MONO_MODULE_CFLAGS
    and MONO_MODULE_LIBS to avoid the need to call pkg-config.
    See the pkg-config man page for more details.

 m4/mono.m4 | 3 +++
 1 file changed, 3 insertions(+)
---
diff --git a/m4/mono.m4 b/m4/mono.m4
index fc204175..69bd58fb 100644
--- a/m4/mono.m4
+++ b/m4/mono.m4
@@ -32,6 +32,9 @@ AC_DEFUN([SHAMROCK_FIND_MONO_RUNTIME],
 
 AC_DEFUN([SHAMROCK_CHECK_MONO_MODULE],
 [
+       if test "x$(uname)" = "xDarwin"; then
+               export 
PKG_CONFIG_PATH=/Library/Frameworks/Mono.framework/Versions/Current/lib/pkgconfig:$PKG_CONFIG_PATH
+       fi
        PKG_CHECK_MODULES(MONO_MODULE, mono >= $1)
 ])