Run python tests without make install

In order to do this, we need to add some stub gi module init files which
allow us to extend the gi overrides path.

configure.ac

@@ -772,8 +772,6 @@ fi
 
 if test x"$enable_pyvips8" = x"yes"; then
   PKG_CHECK_MODULES(PYGOBJECT, [pygobject-3.0 >= 3.12.0])
-  pyoverridesdir="\$(pyexecdir)/gi/overrides"
-  AC_SUBST(pyoverridesdir)
 fi
 
 AM_CONDITIONAL(ENABLE_PYVIPS8, test x"$enable_pyvips8" = x"yes")
@@ -994,6 +992,9 @@ AC_OUTPUT([
 	tools/light_correct 
 	tools/shrink_width 
 	python/Makefile 
+	python/packages/Makefile
+	python/packages/gi/Makefile 
+	python/packages/gi/overrides/Makefile 
 	test/Makefile 
 	test/variables.sh
 	swig/Makefile 

python/Makefile.am

@@ -1,17 +1,5 @@
-vips_overridesdir = $(pyoverridesdir)
-vips_overrides_PYTHON = Vips.py 
+SUBDIRS = packages
 
 EXTRA_DIST = \
 	README.md
 
-# if we build in a separate tree, we need to symlink the *.py files from the
-# source tree; Python does not accept the extensions and modules in different
-# paths
-build_pylinks:
-	for f in $(vips_overrides_PYTHON); do \
-	    [ -e $(builddir)/$$f ] || $(LN_S) $(srcdir)/$$f $(builddir)/$$f; \
-	done
-
-all-local: build_pylinks
-check-local: build_pylinks
-

python/packages/Makefile.am

@@ -0,0 +1 @@
+SUBDIRS = gi

python/packages/gi/Makefile.am

@@ -0,0 +1,5 @@
+SUBDIRS = overrides
+
+EXTRA_DIST = \
+	__init__.py
+

python/packages/gi/__init__.py

@@ -0,0 +1,3 @@
+# support overrides in different directories than our gi module
+from pkgutil import extend_path
+__path__ = extend_path(__path__, __name__)

python/packages/gi/overrides/Makefile.am

@@ -0,0 +1,5 @@
+vips_overridesdir = $(pyexecdir)/gi/overrides
+vips_overrides_PYTHON = Vips.py
+
+EXTRA_DIST = \
+	__init__.py

python/packages/gi/overrides/__init__.py

@@ -0,0 +1,3 @@
+# support overrides in different directories than our gi module
+from pkgutil import extend_path
+__path__ = extend_path(__path__, __name__)

test/test_all.py

@@ -1,4 +1,7 @@
-#!/usr/bin/python3
+#!/usr/bin/env python
+
+import sys
+sys.path.append('../python/packages')
 
 import unittest