[modules] Flatten -fmodule-name= and -fmodule-implementation-of= into a single
option. Previously these options could both be used to specify that you were
compiling the implementation file of a module, with a different set of minor
bugs in each case.

This change removes -fmodule-implementation-of, and instead tracks a flag to
determine whether we're currently building a module. -fmodule-name now behaves
the same way that -fmodule-implementation-of previously did.

llvm-svn: 261372
diff --git a/clang/test/Modules/explicit-build.cpp b/clang/test/Modules/explicit-build.cpp
index 2a5b70d..a6f6a62 100644
--- a/clang/test/Modules/explicit-build.cpp
+++ b/clang/test/Modules/explicit-build.cpp
@@ -143,7 +143,7 @@
 // -------------------------------
 // Try to import a PCH with -fmodule-file=
 // RUN: %clang_cc1 -x c++ -std=c++11 -fmodules -fimplicit-module-maps -fmodules-cache-path=%t -Rmodule-build -fno-modules-error-recovery \
-// RUN:            -fmodule-name=a -emit-pch %S/Inputs/explicit-build/a.h -o %t/a.pch \
+// RUN:            -fmodule-name=a -emit-pch %S/Inputs/explicit-build/a.h -o %t/a.pch -DBUILDING_A_PCH \
 // RUN:            2>&1 | FileCheck --check-prefix=CHECK-NO-IMPLICIT-BUILD %s --allow-empty
 //
 // RUN: not %clang_cc1 -x c++ -std=c++11 -fmodules -fimplicit-module-maps -fmodules-cache-path=%t -Rmodule-build -fno-modules-error-recovery \