Discourage in-source autoconf builds (as we already do for the cmake build)

[jroelofs]

Now barfs earlier. Needs autoconf to be run on it, though.

Any benefit to having this in both the configure and the makefile, other than to make it slightly harder to do the wrong thing?

[echristo]

None that I can think of.

-eric

[jroelofs]

@echristo twisted my arm... so I built the appropriate autoconf/automake, and generated a new configure. Also discarded the Makefile.config.in change.

[echristo]

LGTM. Thanks!

-eric

[jroelofs]

r230812

Makefile.config.in

 PROJ_SRC_ROOT   := $(LLVM_SRC_ROOT)
 PROJ_SRC_DIR    := $(LLVM_SRC_ROOT)$(patsubst $(PROJ_OBJ_ROOT)%,%,$(PROJ_OBJ_DIR))
 
+ifeq ($(LLVM_SRC_ROOT), $(LLVM_OBJ_ROOT))
+$(error In-source builds are discouraged. Configure from a separate build directory.)
+endif
+
 ifneq ($(CLANG_SRC_ROOT),)
   CLANG_SRC_ROOT:= $(call realpath, $(CLANG_SRC_ROOT))
   PROJ_SRC_DIR  := $(patsubst $(LLVM_SRC_ROOT)/tools/clang%,$(CLANG_SRC_ROOT)%,$(PROJ_SRC_DIR))

autoconf/configure.ac

   fi
 fi
 
+dnl Quit if it is an in-source build
+if test ${srcdir} == "." ; then
+  AC_MSG_ERROR([In-source builds are discouraged. Configure from a separate build directory.])
+fi
+
 dnl Default to empty (i.e. assigning the null string to) CFLAGS and CXXFLAGS,
 dnl instead of the autoconf default (for example, '-g -O2' for CC=gcc).
 : ${CFLAGS=}