testsuite: Force use of -c when precompiling headers

In some configurations of our validation setup, we always call the
compiler with -Wl,-rpath=XXX, which instructs the driver to invoke the
linker if none of -c, -S or -E is used.

This happens to be the case in the PCH tests, where dg-flags-pch sets
dg-do-what-default to precompile.

This works most of the time, in absence of any linker option, the
compiler defaults to generating a precompiled header (otherwise the
linker complains because it cannot find 'main').

This small patch forces the use of '-c' when generating the .gch file,
which is sufficient not to invoke the linker.

Arguably, this could be seen as a dejagnu bug: in gcc-dg-test-1 (in
gcc-dg.exp), we set compile_type to "precompiled_header", which is not
one of the supported values in dejagnu's default_target_compile (in
target.exp).

2023-10-27  Christophe Lyon  <christophe.lyon@linaro.org>

	gcc/testsuite/
	* lib/dg-pch.exp (dg-flags-pch): Add -c when generating the
	precompiled header.

0 files changed, 0 insertions, 0 deletions