[gobject-introspection/mallard-templates] g-ir-doc-tool: Add AM_CHECK_PYMOD macro and use it to check for Mako

[Tomeu Vizoso <tomeuv src gnome org>]

commit a7befa29ae7252327eca9394fa866338a51dea11
Author: Tomeu Vizoso <tomeu vizoso collabora com>
Date:   Mon Feb 20 15:01:30 2012 +0100

    g-ir-doc-tool: Add AM_CHECK_PYMOD macro and use it to check for Mako

 configure.ac |    2 ++
 m4/python.m4 |   37 +++++++++++++++++++++++++++++++++++++
 2 files changed, 39 insertions(+), 0 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index df79645..c311f66 100644
--- a/configure.ac
+++ b/configure.ac
@@ -272,6 +272,8 @@ if test "x$os_win32" = "xyes"; then
   AM_CHECK_PYTHON_LIBS(, AC_MSG_ERROR([Python libs not found. Windows requires Python modules to be explicitly linked to libpython.]))
 fi
 
+AM_CHECK_PYMOD(mako,,,[AC_MSG_ERROR(Could not find python module: mako)])
+
 # Glib documentation
 
 GLIBSRC=
diff --git a/m4/python.m4 b/m4/python.m4
index c939c43..74ac6ee 100644
--- a/m4/python.m4
+++ b/m4/python.m4
@@ -1,4 +1,41 @@
 ## this one is commonly used with AM_PATH_PYTHONDIR ...
+dnl AM_CHECK_PYMOD(MODNAME [,SYMBOL [,ACTION-IF-FOUND [,ACTION-IF-NOT-FOUND]]])
+dnl Check if a module containing a given symbol is visible to python.
+AC_DEFUN([AM_CHECK_PYMOD],
+[AC_REQUIRE([AM_PATH_PYTHON])
+py_mod_var=`echo $1['_']$2 | sed 'y%./+-%__p_%'`
+AC_MSG_CHECKING(for ifelse([$2],[],,[$2 in ])python module $1)
+AC_CACHE_VAL(py_cv_mod_$py_mod_var, [
+ifelse([$2],[], [prog="
+import sys
+try:
+        import $1
+except ImportError:
+        sys.exit(1)
+except:
+        sys.exit(0)
+sys.exit(0)"], [prog="
+import $1
+$1.$2"])
+if $PYTHON -c "$prog" 1>&AC_FD_CC 2>&AC_FD_CC
+  then
+    eval "py_cv_mod_$py_mod_var=yes"
+  else
+    eval "py_cv_mod_$py_mod_var=no"
+  fi
+])
+py_val=`eval "echo \`echo '$py_cv_mod_'$py_mod_var\`"`
+if test "x$py_val" != xno; then
+  AC_MSG_RESULT(yes)
+  ifelse([$3], [],, [$3
+])dnl
+else
+  AC_MSG_RESULT(no)
+  ifelse([$4], [],, [$4
+])dnl
+fi
+])
+
 dnl a macro to check for ability to create python extensions
 dnl  AM_CHECK_PYTHON_HEADERS([ACTION-IF-POSSIBLE], [ACTION-IF-NOT-POSSIBLE])
 dnl function also defines PYTHON_INCLUDES