--- a/CPP/7zip/7zip_gcc.mak
+++ b/CPP/7zip/7zip_gcc.mak
@@ -24,7 +24,7 @@ PROGPATH_STATIC = $(O)/$(PROG)s
 
 
 ifneq ($(CC), xlc)
-CFLAGS_WARN_WALL = -Werror -Wall -Wextra
+CFLAGS_WARN_WALL = -Wall -Wextra
 endif
 
 # for object file
@@ -32,7 +32,7 @@ endif
 # -save-temps
 CFLAGS_BASE_LIST = -c
 # CFLAGS_BASE_LIST = -S
-CFLAGS_BASE = -O2 $(CFLAGS_BASE_LIST) $(CFLAGS_WARN_WALL) $(CFLAGS_WARN) \
+CFLAGS_BASE = $(CFLAGS_BASE_LIST) $(CFLAGS_WARN_WALL) $(CFLAGS_WARN) -D_GNU_SOURCE \
  -DNDEBUG -D_REENTRANT -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE \
  -fPIC
 
@@ -149,7 +149,7 @@ endif
 
 
 
-CFLAGS = $(MY_ARCH_2) $(LOCAL_FLAGS) $(CFLAGS_BASE2) $(CFLAGS_BASE) $(FLAGS_FLTO) $(CC_SHARED) -o $@
+CFLAGS += $(MY_ARCH_2) $(LOCAL_FLAGS) $(CFLAGS_BASE2) $(CFLAGS_BASE) $(FLAGS_FLTO) $(CC_SHARED) -o $@
 
 
 ifdef IS_MINGW
@@ -208,7 +208,7 @@ $(O):
 # -Wl,--print-gc-sections
 
 ifneq ($(CC), $(CROSS_COMPILE)clang)
-LFLAGS_STRIP = -s
+LFLAGS_STRIP =
 endif
 
 LFLAGS_ALL = $(LFLAGS_STRIP) $(MY_ARCH_2) $(LDFLAGS) $(FLAGS_FLTO) $(LD_arch) $(OBJS) $(MY_LIBS) $(LIB2)
@@ -1285,7 +1285,7 @@ predef_cc:
 	$(CC) $(CFLAGS) -E $(SHOW_PREDEF)  ../../../../C/CpuArch.c > predef_cc_log
 #	$(CC) $(CFLAGS) -E -dM -  < /dev/null
 predef_cxx:
-	$(CXX) $(CFLAGS) -E $(SHOW_PREDEF) ../../../Common/CrcReg.cpp  > predef_cxx_log
+	$(CXX) $(CXXFLAGS) -E $(SHOW_PREDEF) ../../../Common/CrcReg.cpp  > predef_cxx_log
 
 predef: predef_cc predef_cxx