Building PETSc with clang++ produces a warning about compiling *.c as C++ being deprecated. To silence the warning, we would need to pass "-x c++" to the compiler, but NOT to the linker. CFLAGS is currently also passed to the linker. Is this something we want to fix?
According to autoconf, CFLAGS goes with both. CPPFLAGS is only for the compiler.
Matt
Clang used to SEGV when "-x c++" is passed to the linker. Now (latest SVN) it just interprets the object file as C++ source (which obviously produces a ton of garbage).