Merge pull request #2 from Redfoxymoon/master

Portability fixes for building against musl libc distros

doomgeneric/Makefile

@@ -15,7 +15,7 @@ endif
 CC=gcc  # gcc or g++
 CFLAGS+=-ggdb3 -Os
 LDFLAGS+=-Wl,--gc-sections
-CFLAGS+=-ggdb3 -Wall -DNORMALUNIX -DLINUX -DSNDSERV # -DUSEASM
+CFLAGS+=-ggdb3 -Wall -DNORMALUNIX -DLINUX -DSNDSERV -D_DEFAULT_SOURCE # -DUSEASM
 LIBS+=-lm -lc -lX11
 
 # subdirectory for objects

doomgeneric/doomgeneric.h

@@ -1,6 +1,7 @@
 #ifndef DOOM_GENERIC
 #define DOOM_GENERIC
 
+#include <stdlib.h>
 #include <stdint.h>
 
 #define DOOMGENERIC_RESX 640

doomgeneric/doomgeneric_xlib.c

@@ -2,6 +2,7 @@
 
 #include "doomgeneric.h"
 
+#include <ctype.h>
 #include <stdio.h>
 #include <string.h>
 #include <unistd.h>