remove hardcoded -O flags
use bsd platform path

Index: src/Makefile
--- src/Makefile.orig
+++ src/Makefile
@@ -39,8 +39,6 @@ LDLIBS := $(LDLIBS)
 
 ifdef FHEROES2_WITH_DEBUG
 CCFLAGS := $(CCFLAGS) -O0 -g
-else
-CCFLAGS := $(CCFLAGS) -O3
 endif
 
 ifneq ($(or $(FHEROES2_WITH_ASAN),$(FHEROES2_WITH_TSAN)),)
@@ -67,6 +65,9 @@ OS := $(shell uname)
 endif
 
 ifeq ($(OS),FreeBSD)
+PLATFORM := bsd
+endif
+ifeq ($(OS),OpenBSD)
 PLATFORM := bsd
 endif
 ifeq ($(OS),Darwin)
