try to choose correct python version using gdb

Makefile

@@ -1,7 +1,5 @@
 # This is passed to pkg-config to determine which python to use.  It
 # has to match your gdb.
-pyname = python
-
 all: gdb-gui.py gui/fix_signals.so
 	@:
 
@@ -9,7 +7,8 @@ gdb-gui.py: gdb-gui.py.in
 	sed -e "s,HERE,`pwd`," < gdb-gui.py.in > gdb-gui.py
 
 gui/fix_signals.so: gui/fix-signals.c
-	gcc -shared -fPIC -g -o gui/fix_signals.so gui/fix-signals.c `pkg-config --cflags $(pyname)` `pkg-config --libs $(pyname)`
+	pyver=`gdb -nx -batch -ex 'python print(sys.version_info.major)'`; \
+	gcc -shared -fPIC -g -o gui/fix_signals.so gui/fix-signals.c `pkg-config --cflags python$$pyver` `pkg-config --libs python$$pyver`
 
 clean:
 	-rm gdb-gui.py gui/fix_signals.so