pm:cpupower: Add error warning when SWIG is not installed

Add error message to better explain to the user when SWIG and
python-config is missing from the path. Makefile was cleaned up
and unneeded elements were removed.
Suggested-by: Shuah Khan <skhan@linuxfoundation.org>
Signed-off-by: John B. Wyatt IV <jwyatt@redhat.com>
Signed-off-by: John B. Wyatt IV <sageofredondo@gmail.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

tools/power/cpupower/bindings/python/Makefile

@@ -4,26 +4,28 @@
 # This Makefile expects you have already run the makefile for cpupower to build
 # the .o files in the lib directory for the bindings to be created.
 
-CC=gcc
-
-LIB_DIR = ../../lib
-BIND_DIR = .
-PY_INCLUDE := $(firstword $(shell python-config --includes))
-#PY_INCLUDE = $(shell python-config --includes | awk '{ print $1 }')
+CC := gcc
+HAVE_SWIG := $(shell if which swig >/dev/null 2>&1; then echo 1; else echo 0; fi)
+HAVE_PYCONFIG := $(shell if which python-config >/dev/null 2>&1; then echo 1; else echo 0; fi)
 
+LIB_DIR := ../../lib
+PY_INCLUDE = $(firstword $(shell python-config --includes))
 OBJECTS_LIB = $(wildcard $(LIB_DIR)/*.o)
-OBJECTS_BIND = $(wildcard $(BIND_DIR)/*.o)
 
 all: _raw_pylibcpupower.so
 
 _raw_pylibcpupower.so: raw_pylibcpupower_wrap.o
-	$(CC) -shared $(OBJECTS_LIB) raw_pylibcpupower_wrap.o -o _raw_pylibcpupower.so # raw_pylibcpupower_wrap.o
-#	$(CC) -shared $(OBJECTS_BIND) $(OBJECTS_LIB) -o _raw_pylibcpupower.so # raw_pylibcpupower_wrap.o
+	$(CC) -shared $(OBJECTS_LIB) raw_pylibcpupower_wrap.o -o _raw_pylibcpupower.so
 
 raw_pylibcpupower_wrap.o: raw_pylibcpupower_wrap.c
 	$(CC) -fPIC -c raw_pylibcpupower_wrap.c $(PY_INCLUDE)
 
 raw_pylibcpupower_wrap.c: raw_pylibcpupower.i
+ifeq ($(HAVE_SWIG),0)
+	$(error "swig was not found. Make sure you have it installed and in the PATH to generate the bindings.")
+else ifeq ($(HAVE_PYCONFIG),0)
+	$(error "python-config was not found. Make sure you have it installed and in the PATH to generate the bindings.")
+endif
 	swig -python raw_pylibcpupower.i
 
 # Will only clean the bindings folder; will not clean the actual cpupower folder