Add make target "format" to run "go fmt" on Go files.

configure.ac

@@ -43,7 +43,7 @@ AC_SUBST(HAVE_GO)
 AM_CONDITIONAL(MINGW, expr $host : '.*-mingw' >/dev/null 2>&1)
 
 AM_INIT_AUTOMAKE([foreign])
-AM_EXTRA_RECURSIVE_TARGETS([test])
+AM_EXTRA_RECURSIVE_TARGETS([format test])
 
 AX_CXX_COMPILE_STDCXX_11()
 

examples/Makefile.am

@@ -86,4 +86,12 @@ gopath:
 
 heif-test-go: gopath $(top_builddir)/libheif/libheif.la $(top_builddir)/libheif.pc heif-test.go
 	GOPATH=${CURDIR} PKG_CONFIG_PATH=$(abs_top_builddir) CGO_CFLAGS="-I$(abs_top_builddir)" CGO_LDFLAGS="-L$(abs_top_builddir)/libheif/.libs" LD_LIBRARY_PATH=$(abs_top_builddir)/libheif/.libs $(GO) build -o heif-test-go heif-test.go
+
+format-go: heif-test.go
+	$(GO) fmt heif-test.go
+else
+format-go:
+	echo ""go" not present in "${PATH}", skipping formatting"
 endif
+
+format-local: format-go

go/Makefile.am

@@ -7,9 +7,17 @@ gopath:
 if HAVE_GO
 test-go: gopath $(top_builddir)/libheif/libheif.la $(top_builddir)/libheif.pc
 	GOPATH=${CURDIR} PKG_CONFIG_PATH=$(abs_top_builddir) CGO_CFLAGS="-I$(abs_top_builddir)" CGO_LDFLAGS="-L$(abs_top_builddir)/libheif/.libs" LD_LIBRARY_PATH=$(abs_top_builddir)/libheif/.libs $(GO) test -v heif
+
+format-go: gopath
+	GOPATH=${CURDIR} $(GO) fmt heif
 else
 test-go:
 	echo ""go" not present in "${PATH}", skipping tests"
+
+format-go:
+	echo ""go" not present in "${PATH}", skipping formatting"
 endif
 
 test-local: test-go
+
+format-local: format-go