Only cross-test 32bit on Linux (#658)

This doesn't work on at least FreeBSD and Darwin. It does work on Linux,
only try it there.

1 files changed, 7 insertions, 5 deletions

diff --git a/Makefile b/Makefile
index b10d5a4..b1d6d6b 100644
--- a/Makefile
+++ b/Makefile
@@ -41,10 +41,12 @@ endif
 # 64bit -> 32bit mapping for cross-checking. At least for amd64/386, the 64bit CPU can execute 32bit code but not the other way around, so we don't support cross-testing upwards.
 cross-test = skip-test-32bit
 define goarch_pair
-ifeq ($$(GOARCH),$1)
-        GOARCH_CROSS = $2
-        cross-test = test-32bit
-endif
+        ifeq ($$(OS_detected),Linux)
+                ifeq ($$(GOARCH),$1)
+                        GOARCH_CROSS = $2
+                        cross-test = test-32bit
+                endif
+        endif
 endef
 
 # By default, "cross" test with ourselves to cover unknown pairings.
@@ -68,7 +70,7 @@ test-32bit: collector/fixtures/sys/.unpacked
         @env GOARCH=$(GOARCH_CROSS) $(GO) test $(pkgs)
 
 skip-test-32bit:
-        @echo ">> SKIP running tests in 32-bit mode: not supported on $(GOARCH)"
+        @echo ">> SKIP running tests in 32-bit mode: not supported on $(OS_detected)/$(GOARCH)"
 
 collector/fixtures/sys/.unpacked: collector/fixtures/sys.ttar
         ./ttar -C collector/fixtures -x -f collector/fixtures/sys.ttar