From d9166b52cf3458a4da3eb92224837ca8fc208d79 Mon Sep 17 00:00:00 2001 From: Jia Tan Date: Mon, 24 Jul 2023 21:43:44 +0800 Subject: [PATCH] liblzma: Prevent an empty translation unit in Windows builds. To workaround Automake lacking Windows resource compiler support, an empty source file is compiled to overwrite the resource files for static library builds. Translation units without an external declaration are not allowed by the C standard and result in a warning when used with -Wempty-translation-unit (Clang) or -pedantic (GCC). --- src/liblzma/Makefile.am | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/src/liblzma/Makefile.am b/src/liblzma/Makefile.am index 0751f7a6..13453e72 100644 --- a/src/liblzma/Makefile.am +++ b/src/liblzma/Makefile.am @@ -72,11 +72,15 @@ endif # static liblzma, we overwrite the static object file with an object file # compiled from empty input. Note that GNU-specific features are OK here, # because on Windows we are compiled with the GNU toolchain. +# +# The typedef in empty.c will prevent an empty translation unit, which is +# not allowed by the C standard. It results in a warning with +# -Wempty-translation-unit with Clang or -pedantic for GCC. .rc.lo: $(LIBTOOL) --mode=compile $(RC) $(DEFS) $(DEFAULT_INCLUDES) \ $(INCLUDES) $(liblzma_la_CPPFLAGS) $(CPPFLAGS) $(RCFLAGS) \ -i $< -o $@ - echo > empty.c + echo "typedef void empty;" > empty.c $(COMPILE) -c empty.c -o $(*D)/$(*F).o # Remove ordinals from the generated .def file. People must link by name,