remove -pedantic from CFLAGS to make travis /w old gcc happy

Makefile

@@ -6,7 +6,7 @@ VPKDIR ?= ~/.local/share/Steam/steamapps/common/Half-Life\ 2/hl2
 MAX_MAPS ?= 32
 ARGS ?= -p $(VPKDIR)/hl2_textures_dir.vpk -p $(VPKDIR)/hl2_misc_dir.vpk -p $(VPKDIR)/hl2_pak_dir.vpk -d $(VPKDIR) -n $(MAX_MAPS)
 
-CFLAGS += -Wall -Wextra -pedantic -D_GNU_SOURCE -Isrc/atto -fPIE
+CFLAGS += -Wall -Wextra -D_GNU_SOURCE -Isrc/atto -fPIE
 LIBS = -lX11 -lXfixes -lGL -lm -pthread
 BUILDDIR ?= build