try_compile: Add signature to allow multiple SOURCES

Extend the signature

 try_compile(RESULT_VAR <bindir> <srcfile> ...)

to allow multiple sources as

 try_compile(RESULT_VAR <bindir> SOURCES <srcfile>... ...)

Process the sources to generate a CMakeLists.txt that enables all needed
languages.

Teach the TryCompile test to try cases with two sources of the same
language and of mixed languages.  Teach RunCMake.try_compile to cover
error cases for the signature.

1 files changed, 2 insertions, 0 deletions

diff --git a/Tests/TryCompile/pass2a.c b/Tests/TryCompile/pass2a.c
new file mode 100644
index 0000000..bbfe6d5
--- /dev/null
+++ b/Tests/TryCompile/pass2a.c
@@ -0,0 +1,2 @@
+extern int pass2b(void);
+int main() { return pass2b(); }