fix FindLib makefile to make it buildable standalone

Copy the "features" CFLAGS portion and some missing defines from the main makefile to fix the
standalone build of FindLib.

Change the definition of OBJ_DIR to match the main makefile.

FindLib may be useful as a standalone library which could be packaged separately and TraX made
dependendent on it.

FindLib/etc/makefile

@@ -1,6 +1,7 @@
 ### makefile for findlib
 
-OBJ_DIR := obj
+SYS_VERS  := r$(shell uname -r)
+OBJ_DIR := obj.$(SYS_VERS)
 DEP_DIR := depends
 
 
@@ -9,13 +10,27 @@ DEP_DIR := depends
 OPTIMIZER		=	-O0
 
 CC		     	=	gcc
-CFLAGS			=	$(OPTIMIZER) -Wall -Wno-multichar -Wno-ctor-dtor-privacy
+
+# This is needed to be able to compile on either nightlies, or beta4.
+# See https://dev.haiku-os.org/ticket/11818 (fixed for good in hrev57497).
+# We can simplify this once the haikuports buildmasters switch to beta5.
+
+HAIKU_HREV_NUM = $(shell uname -v | cut -d " " -f 1 | cut -d "+" -f 1 | sed s/hrev//)
+HAS_FIXED_FEATURES_H = $(shell if [ $(strip $(HAIKU_HREV_NUM)) -ge 57497 ]; then echo "YES"; else echo "NO"; fi)
+
+ifeq ($(strip $(HAS_FIXED_FEATURES_H)), YES)
+	CFLAGS	=	$(OPTIMIZER) -Wall -Wno-multichar -Wno-ctor-dtor-privacy -D_DEFAULT_SOURCE -DSTDC_HEADERS
+else
+	CFLAGS	=	$(OPTIMIZER) -Wall -Wno-multichar -Wno-ctor-dtor-privacy -D__USE_GNU -DSTDC_HEADERS
+endif
 
 LD				=	gcc
 LDFLAGS			=	
-SHAREDLIB_FLAGS	=	-nostart -Xlinker -soname=$(notdir $@)
+SHAREDLIB_FLAGS	=	-shared -Xlinker -soname=$(notdir $@)
 
 
+MAKE_DEPEND		 = ../../etc/MakeDepend.sh $(CFLAGS) -c $< -dep $@
+MAKE_CC			 = $(CC) $(CFLAGS) -c $< -o $@
 
 
 FINDLIB_DIR := ..