[tomboy] configure.in: update Mono.Cairo check to be version-agnostic

[Alex Tereschenko <alexter src gnome org>]

commit e128f0ad07c8f6614ffae73dc849fda113ee9d13
Author: Alex Tereschenko <frozen and blue gmail com>
Date:   Sat Aug 20 22:29:51 2016 +0200

    configure.in: update Mono.Cairo check to be version-agnostic
    
    Instead of hardcoding paths, which are valid for Mono 2.0 only,
    let's use the standard gacutil tool. As long as we check for Mono
    earlier in the script, we won't do any sophisticated checks for
    this tool specifically to keep it simple.

 configure.in |   13 ++++++-------
 1 files changed, 6 insertions(+), 7 deletions(-)
---
diff --git a/configure.in b/configure.in
index c2670d6..ca057d6 100644
--- a/configure.in
+++ b/configure.in
@@ -213,20 +213,19 @@ AC_SUBST(GTKSHARP_LIBS)
 required_assemblies="Mono.Cairo"
 
 #
-# This check stolen from banshee/build/m4/shamrock/mono.m4, because pkg-config
-# seems to find the wrong Mono.Cairo (1.0).
+# By now we should have found Mono installation, so we can assume gacutil is available.
+# gacutil prints out a string like below only if assembly with given name is found:
+# Mono.Cairo, Version=4.0.0.0, Culture=neutral, PublicKeyToken=0738eb9f132ed756
 #
 for asm in $required_assemblies
 do
-       AC_MSG_CHECKING([for Mono 2.0 GAC for $asm.dll])
-       if test \
-               -e "$($PKG_CONFIG --variable=libdir mono)/mono/2.0/$asm.dll" -o \
-               -e "$($PKG_CONFIG --variable=prefix mono)/lib/mono/2.0/$asm.dll"; \
+       AC_MSG_CHECKING([for Mono GAC for $asm.dll])
+       if ( gacutil -l $asm |grep -q $asm );
                then \
                AC_MSG_RESULT([found])
        else
                AC_MSG_RESULT([not found])
-               AC_MSG_ERROR([missing reqired Mono 2.0 assembly: $asm.dll])
+               AC_MSG_ERROR([missing reqired Mono assembly: $asm.dll])
        fi
 done