Properly set architecture flags for both compiler and linker

Makefile

@@ -126,9 +126,9 @@ $(call ensure_binary,$(PKG_CONFIG))
 
 override CFLAGS += -std=c++11 -Wall -Wextra -pedantic -O2 -g
 
-GCC_4_2_OR_HIGHER := $(shell expr `$(CXX) -dumpversion | sed 's/\.//g'` \>= 420)
-ifeq "$(GCC_4_2_OR_HIGHER)" "1"
-    CFLAGS += -march=native
+ifeq ($(ARCH),i386)
+  override CFLAGS += -m32
+  override LFLAGS += -m32
 endif
 
 DEFINES = -DFUSE_USE_VERSION=26

docker-compose.yaml

@@ -28,7 +28,6 @@ services:
       - *src-volume
       - linux-gcc-32:/build
     environment:
-      - CFLAGS=-m32
       - ARCH=i386
 
   linux-gcc-64: