Don't use c99 -MM -MT.

These are non-POSIX flags that only work on some compilers. Notably,
the BSD c99 executables don't support them.

configure

@@ -128,11 +128,26 @@ print_obj() {
 	printf '%s ' "$2"
 }
 
+get_deps() {
+    src="$1"
+
+    ${CC} -I${INCLUDE} -E "$src" \
+        | grep '^#'              \
+        | awk '{print $3}'       \
+        | cut -d '"' -f 2        \
+        | sort                   \
+        | uniq                   \
+        | grep -v '^[/<]'        \
+        | while IFS= read -r dep; do
+        printf "%s " "$dep"
+    done
+}
+
 compile_obj() {
 	src="$1"
 	obj="$2"
 
-	${CC} -I${INCLUDE} -MM -MT "${obj}" "${src}"
+	echo "${obj}: $(get_deps ${src})"
 	echo "${TAB}@mkdir -p $(dirname ${obj})"
 	echo "${TAB}\$(CC) \$(CFLAGS) -fPIC -c -o \"${obj}\" \"${src}\""
 }