Experimental option to build blender as a python module, rather then blender embedding python.

CMake build option WITH_PYTHON_MODULE, will build ./bin/bpy.so

This allows 'bpy' to be imported from python or other applications/IDE's which embed python, eg:
   python -c "import bpy ; bpy.ops.render.render(write_still=True)"

This runs in background mode and has similar restrictions to running a script:
   blender --background --python test.py

TODO:
 - install to site-packages with blender scripts
 - add support for imp.reload()

source/creator/CMakeLists.txt

@@ -127,8 +127,21 @@ if(WITH_BUILDINFO)
 endif()
 
 # message(STATUS "Configuring blender")
+if(WITH_PYTHON_MODULE)
+	add_definitions(-DWITH_PYTHON_MODULE)
 
-add_executable(blender ${EXETYPE} ${SRC})
+	# creates ./bin/bpy.so which can be imported as a python module.
+	add_library(blender SHARED ${SRC})
+	set_target_properties(
+		blender
+		PROPERTIES
+			 PREFIX ""
+			 OUTPUT_NAME bpy
+			 LIBRARY_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/bin/
+	)
+else()
+	add_executable(blender ${EXETYPE} ${SRC})
+endif()
 
 # Post build steps for bundling/packaging.
 

source/creator/creator.c

@@ -154,6 +154,7 @@ static void fpe_handler(int UNUSED(sig))
 }
 #endif
 
+#ifdef WITH_PYTHON_MODULE
 /* handling ctrl-c event in console */
 static void blender_esc(int sig)
 {
@@ -170,6 +171,7 @@ static void blender_esc(int sig)
 		count++;
 	}
 }
+#endif
 
 /* buildinfo can have quotes */
 #ifdef BUILD_DATE
@@ -1111,12 +1113,21 @@ static void setupArguments(bContext *C, bArgs *ba, SYS_SystemHandle *syshandle)
 
 }
 
-int main(int argc, char **argv)
+#ifdef WITH_PYTHON_MODULE
+/* allow python module to call main */
+#define main main_python
+#endif
+
+int main(int argc, const char **argv)
 {
 	SYS_SystemHandle syshandle;
 	bContext *C= CTX_create();
 	bArgs *ba;
 
+#ifdef WITH_PYTHON_MODULE
+#undef main
+#endif
+
 #ifdef WITH_BINRELOC
 	br_init( NULL );
 #endif
@@ -1192,10 +1203,13 @@ int main(int argc, char **argv)
 	setuid(getuid()); /* end superuser */
 #endif
 
-
+#ifdef WITH_PYTHON_MODULE
+	G.background= 1; /* python module mode ALWAYS runs in background mode (for now) */
+#else
 	/* for all platforms, even windos has it! */
 	if(G.background) signal(SIGINT, blender_esc);	/* ctrl c out bg render */
-	
+#endif
+
 	/* background render uses this font too */
 	BKE_font_register_builtin(datatoc_Bfont, datatoc_Bfont_size);
 
@@ -1248,6 +1262,10 @@ int main(int argc, char **argv)
 
 	BLI_argsFree(ba);
 
+#ifdef WITH_PYTHON_MODULE
+	return 0; /* keep blender in background mode running */
+#endif
+
 	if(G.background) {
 		/* actually incorrect, but works for now (ton) */
 		WM_exit(C);