[commit: ghc] wip/forall-keyword, wip/hadrian-wcompat, wip/no-kind-vars: configure: Document CLANG, LLC, and OPT variables (2868313)

[git at git.haskell.org]

Repository : ssh://git@git.haskell.org/ghc

On branches: wip/forall-keyword,wip/hadrian-wcompat,wip/no-kind-vars
Link       : http://ghc.haskell.org/trac/ghc/changeset/28683137a59607dfdac6add35aefc8676b7fa864/ghc

>---------------------------------------------------------------

commit 28683137a59607dfdac6add35aefc8676b7fa864
Author: Ben Gamari <ben at smart-cactus.org>
Date:   Sat Feb 9 17:34:36 2019 -0500

    configure: Document CLANG, LLC, and OPT variables


>---------------------------------------------------------------

28683137a59607dfdac6add35aefc8676b7fa864
 configure.ac            | 3 +++
 distrib/configure.ac.in | 2 ++
 2 files changed, 5 insertions(+)

diff --git a/configure.ac b/configure.ac
index b75220d..e269b96 100644
--- a/configure.ac
+++ b/configure.ac
@@ -648,18 +648,21 @@ AC_DEFINE_UNQUOTED([sUPPORTED_LLVM_VERSION], ${sUPPORTED_LLVM_VERSION}, [The sup
 
 dnl ** Which LLVM clang to use?
 dnl --------------------------------------------------------------
+AC_ARG_VAR(CLANG,[Use as the path to clang [default=autodetect]])
 AC_CHECK_TARGET_TOOL([CLANG], [clang])
 ClangCmd="$CLANG"
 AC_SUBST([ClangCmd])
 
 dnl ** Which LLVM llc to use?
 dnl --------------------------------------------------------------
+AC_ARG_VAR(LLC,[Use as the path to LLVM's llc [default=autodetect]])
 FIND_LLVM_PROG([LLC], [llc], [$LlvmVersion])
 LlcCmd="$LLC"
 AC_SUBST([LlcCmd])
 
 dnl ** Which LLVM opt to use?
 dnl --------------------------------------------------------------
+AC_ARG_VAR(OPT,[Use as the path to LLVM's opt [default=autodetect]])
 FIND_LLVM_PROG([OPT], [opt], [$LlvmVersion])
 OptCmd="$OPT"
 AC_SUBST([OptCmd])
diff --git a/distrib/configure.ac.in b/distrib/configure.ac.in
index e064a5d..dd0eb2e 100644
--- a/distrib/configure.ac.in
+++ b/distrib/configure.ac.in
@@ -128,12 +128,14 @@ LlvmVersion=@LlvmVersion@
 
 dnl ** Which LLVM llc to use?
 dnl --------------------------------------------------------------
+AC_ARG_VAR(LLC,[Use as the path to LLVM's llc [default=autodetect]])
 FIND_LLVM_PROG([LLC], [llc], [$LlvmVersion])
 LlcCmd="$LLC"
 AC_SUBST([LlcCmd])
 
 dnl ** Which LLVM opt to use?
 dnl --------------------------------------------------------------
+AC_ARG_VAR(OPT,[Use as the path to LLVM's opt [default=autodetect]])
 FIND_LLVM_PROG([OPT], [opt], [$LlvmVersion])
 OptCmd="$OPT"
 AC_SUBST([OptCmd])