autoconf: Add --disable-embed-stdcxx to suppress linking libstdc++.a into llvm.dll with --enable-shared on Cygming.

Cygwin has stdc++.dll in it's distribution, and we can assume distro's stdc++.dll might be available.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122622 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/configure b/configure
index ac24889..2a739d3 100755
--- a/configure
+++ b/configure
@@ -694,6 +694,7 @@
 ENABLE_PTHREADS
 ENABLE_PIC
 ENABLE_SHARED
+ENABLE_EMBED_STDCXX
 ENABLE_TIMESTAMPS
 TARGETS_TO_BUILD
 LLVM_ENUM_TARGETS
@@ -1421,6 +1422,8 @@
                           is YES)
   --enable-shared         Build a shared library and link tools against it
                           (default is NO)
+  --enable-embed-stdcxx   Build a shared library with embedded libstdc++ for
+                          Win32 DLL (default is YES)
   --enable-timestamps     Enable embedding timestamp information in build
                           (default is YES)
   --enable-targets        Build specific host targets: all or
@@ -4999,6 +5002,25 @@
    { (exit 1); exit 1; }; } ;;
 esac
 
+# Check whether --enable-embed-stdcxx was given.
+if test "${enable_embed_stdcxx+set}" = set; then
+  enableval=$enable_embed_stdcxx;
+else
+  enableval=default
+fi
+
+case "$enableval" in
+  yes) ENABLE_EMBED_STDCXX=1
+ ;;
+  no)  ENABLE_EMBED_STDCXX=0
+ ;;
+  default) ENABLE_EMBED_STDCXX=1
+ ;;
+  *) { { echo "$as_me:$LINENO: error: Invalid setting for --enable-embed-stdcxx. Use \"yes\" or \"no\"" >&5
+echo "$as_me: error: Invalid setting for --enable-embed-stdcxx. Use \"yes\" or \"no\"" >&2;}
+   { (exit 1); exit 1; }; } ;;
+esac
+
 # Check whether --enable-timestamps was given.
 if test "${enable_timestamps+set}" = set; then
   enableval=$enable_timestamps;
@@ -11539,7 +11561,7 @@
   lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
   lt_status=$lt_dlunknown
   cat > conftest.$ac_ext <<EOF
-#line 11542 "configure"
+#line 11564 "configure"
 #include "confdefs.h"
 
 #if HAVE_DLFCN_H
@@ -21812,11 +21834,11 @@
 ENABLE_PTHREADS!$ENABLE_PTHREADS$ac_delim
 ENABLE_PIC!$ENABLE_PIC$ac_delim
 ENABLE_SHARED!$ENABLE_SHARED$ac_delim
+ENABLE_EMBED_STDCXX!$ENABLE_EMBED_STDCXX$ac_delim
 ENABLE_TIMESTAMPS!$ENABLE_TIMESTAMPS$ac_delim
 TARGETS_TO_BUILD!$TARGETS_TO_BUILD$ac_delim
 LLVM_ENUM_TARGETS!$LLVM_ENUM_TARGETS$ac_delim
 LLVM_ENUM_ASM_PRINTERS!$LLVM_ENUM_ASM_PRINTERS$ac_delim
-LLVM_ENUM_ASM_PARSERS!$LLVM_ENUM_ASM_PARSERS$ac_delim
 _ACEOF
 
   if test `sed -n "s/.*$ac_delim\$/X/p" conf$$subs.sed | grep -c X` = 97; then
@@ -21858,6 +21880,7 @@
 ac_delim='%!_!# '
 for ac_last_try in false false false false false :; do
   cat >conf$$subs.sed <<_ACEOF
+LLVM_ENUM_ASM_PARSERS!$LLVM_ENUM_ASM_PARSERS$ac_delim
 LLVM_ENUM_DISASSEMBLERS!$LLVM_ENUM_DISASSEMBLERS$ac_delim
 ENABLE_CBE_PRINTF_A!$ENABLE_CBE_PRINTF_A$ac_delim
 CLANGPATH!$CLANGPATH$ac_delim
@@ -21954,7 +21977,6 @@
 BINDINGS_TO_BUILD!$BINDINGS_TO_BUILD$ac_delim
 ALL_BINDINGS!$ALL_BINDINGS$ac_delim
 OCAML_LIBDIR!$OCAML_LIBDIR$ac_delim
-ENABLE_VISIBILITY_INLINES_HIDDEN!$ENABLE_VISIBILITY_INLINES_HIDDEN$ac_delim
 _ACEOF
 
   if test `sed -n "s/.*$ac_delim\$/X/p" conf$$subs.sed | grep -c X` = 97; then
@@ -21996,13 +22018,14 @@
 ac_delim='%!_!# '
 for ac_last_try in false false false false false :; do
   cat >conf$$subs.sed <<_ACEOF
+ENABLE_VISIBILITY_INLINES_HIDDEN!$ENABLE_VISIBILITY_INLINES_HIDDEN$ac_delim
 RPATH!$RPATH$ac_delim
 RDYNAMIC!$RDYNAMIC$ac_delim
 LIBOBJS!$LIBOBJS$ac_delim
 LTLIBOBJS!$LTLIBOBJS$ac_delim
 _ACEOF
 
-  if test `sed -n "s/.*$ac_delim\$/X/p" conf$$subs.sed | grep -c X` = 4; then
+  if test `sed -n "s/.*$ac_delim\$/X/p" conf$$subs.sed | grep -c X` = 5; then
     break
   elif $ac_last_try; then
     { { echo "$as_me:$LINENO: error: could not make $CONFIG_STATUS" >&5