[gobject-introspection] tests: fix incremental build

[Dieter Verfaillie <dieterv src gnome org>]

commit e8f29e2531a9d2a88da944276ffd396e161deb20
Author: Dieter Verfaillie <dieterv optionexplicit be>
Date:   Wed Nov 28 10:36:19 2012 +0100

    tests: fix incremental build
    
    Running make multiple times caused "mkdir" to complain
    that it could not create those directories because they
    where already there...
    
    https://bugzilla.gnome.org/show_bug.cgi?id=689570

 configure.ac              |    1 +
 tests/doctool/Makefile.am |    4 ++--
 2 files changed, 3 insertions(+), 2 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index f6fd5a0..74a44de 100644
--- a/configure.ac
+++ b/configure.ac
@@ -37,6 +37,7 @@ AM_CONDITIONAL(OS_WIN32, [test "x$os_win32" = "xyes"])
 # Checks for programs.
 AC_PROG_CC
 AM_PROG_CC_C_O
+AC_PROG_MKDIR_P
 
 # Initialize libtool
 LT_PREREQ([2.2])
diff --git a/tests/doctool/Makefile.am b/tests/doctool/Makefile.am
index 60183d0..9ef86f2 100644
--- a/tests/doctool/Makefile.am
+++ b/tests/doctool/Makefile.am
@@ -29,10 +29,10 @@ DocExamples_1_0_gir_FILES = $(libdocexamples_la_SOURCES)
 GIRS += DocExamples-1.0.gir
 
 %-C: %.gir
-	mkdir $*-C ; rm -f $*-C/*.page ; $(INTROSPECTION_DOCTOOL) --language C $*.gir -o $*-C/ && echo "  GEN  $*-C/index.page"
+	$(MKDIR_P) $*-C ; rm -f $*-C/*.page ; $(INTROSPECTION_DOCTOOL) --language C $*.gir -o $*-C/ && echo "  GEN  $*-C/index.page"
 
 %-Python: %.gir
-	mkdir $*-Python ; rm -f $*-Python/*.page ; $(INTROSPECTION_DOCTOOL) --language Python $*.gir -o $*-Python/ && echo "  GEN  $*-Python/index.page"
+	$(MKDIR_P) $*-Python ; rm -f $*-Python/*.page ; $(INTROSPECTION_DOCTOOL) --language Python $*.gir -o $*-Python/ && echo "  GEN  $*-Python/index.page"
 
 %-C.page.check: %-C
 	@diff -u -U 10 $(srcdir)/$*-C-expected $*-C && echo "  TEST  $*-C" && rm -rf $*-C