Respect CC,CFLAGS, fix install paths, don't strip binaries

https://bugs.gentoo.org/show_bug.cgi?id=374805
--- Makefile.in
+++ Makefile.in
@@ -1,12 +1,15 @@
-prefix		= $(DESTDIR)@prefix@
-exec_prefix	= $(DESTDIR)@exec_prefix@
-bindir		= $(DESTDIR)@bindir@
-mandir		= $(DESTDIR)@mandir@
-incdir		= $(DESTDIR)@includedir@
+bindir = @bindir@
+exec_prefix = @exec_prefix@
+includedir = @includedir@
+libdir = @libdir@
+mandir = @mandir@
+mkdir_p = @mkdir_p@
+prefix = @prefix@
+INSTALL = /usr/bin/install
 
 all: all-programs
 
-CFLAGS = -O2 -Wall -Iinclude
+CFLAGS += -Wall -Iinclude
 CPPFLAGS = -DDEBUG_EXE -DRDS_VERSION=\"@VERSION@\" -MD -MP -MF $(@D)/.$(basename $(@F)).d
 
 HEADERS = kernel-list.h pfhack.h include/rds.h
@@ -29,14 +32,14 @@
 all-programs: $(PROGRAMS)
 
 install: $(PROGRAMS)
-	install -d $(bindir)
-	install -m 555 -s $(PROGRAMS) $(bindir)
-	install -d $(mandir)/man1
-	install -d $(mandir)/man7
-	install -m 644 *.1 $(mandir)/man1
-	install -m 644 *.7 $(mandir)/man7
-	install -d $(incdir)/net
-	install -m 444 include/rds.h $(incdir)/net
+	$(INSTALL) -d $(DESTDIR)$(bindir)
+	$(INSTALL) -m 555 $(PROGRAMS) $(DESTDIR)$(bindir)
+	$(INSTALL) -d $(DESTDIR)$(mandir)/man1
+	$(INSTALL) -d $(DESTDIR)$(mandir)/man7
+	$(INSTALL) -m 644 *.1 $(DESTDIR)$(mandir)/man1
+	$(INSTALL) -m 644 *.7 $(DESTDIR)$(mandir)/man7
+	$(INSTALL) -d $(DESTDIR)$(includedir)/net
+	$(INSTALL) -m 444 include/rds.h $(DESTDIR)$(includedir)/net
 
 clean:
 	rm -f $(PROGRAMS) $(CLEAN_OBJECTS)
@@ -47,7 +50,7 @@
 
 
 $(PROGRAMS) : % : %.o $(COMMON_OBJECTS)
-	gcc $(CFLAGS) $(LDFLAGS) -o $@ $^
+	$(CC) $(CFLAGS) $(LDFLAGS) -o $@ $^
 
 LOCAL_DFILES := $(wildcard .*.d)
 ifneq ($(LOCAL_DFILES),)