[gn] port e86a02ce89 (dladdr -> llvm-config.h)

Also set HAVE_DLADDR to 1 on non-Win instead of just on macOS.
That looked like an oversight.

llvm/utils/gn/secondary/llvm/include/llvm/Config/BUILD.gn

@@ -156,7 +156,6 @@ write_cmake_config("config") {
     values += [
       "HAVE_CRASHREPORTER_INFO=1",
       "HAVE_DECL_ARC4RANDOM=1",
-      "HAVE_DLADDR=1",
       "HAVE_MACH_MACH_H=1",
       "HAVE_MALLOC_MALLOC_H=1",
       "HAVE_MALLOC_ZONE_STATISTICS=1",
@@ -168,7 +167,6 @@ write_cmake_config("config") {
     values += [
       "HAVE_CRASHREPORTER_INFO=",
       "HAVE_DECL_ARC4RANDOM=",
-      "HAVE_DLADDR=",
       "HAVE_MACH_MACH_H=",
       "HAVE_MALLOC_MALLOC_H=",
       "HAVE_MALLOC_ZONE_STATISTICS=",
@@ -207,7 +205,6 @@ write_cmake_config("config") {
   if (current_os == "win") {
     values += [
       "HAVE_DECL_STRERROR_S=1",
-      "HAVE_DLFCN_H=",
       "HAVE_DLOPEN=",
       "HAVE_FUTIMES=",
       "HAVE_GETPAGESIZE=",
@@ -242,7 +239,6 @@ write_cmake_config("config") {
     # POSIX-y system defaults.
     values += [
       "HAVE_DECL_STRERROR_S=",
-      "HAVE_DLFCN_H=1",
       "HAVE_DLOPEN=1",
       "HAVE_FUTIMES=1",
       "HAVE_GETPAGESIZE=1",
@@ -362,12 +358,16 @@ write_cmake_config("llvm-config") {
 
   if (current_os == "win") {
     values += [
+      "HAVE_DLADDR=",
+      "HAVE_DLFCN_H=",
       "HAVE_SYSEXITS_H=",
       "LLVM_ENABLE_PLUGINS=",
       "LLVM_ON_UNIX=",
     ]
   } else {
     values += [
+      "HAVE_DLADDR=1",
+      "HAVE_DLFCN_H=1",
       "HAVE_SYSEXITS_H=1",
       "LLVM_ENABLE_PLUGINS=1",
       "LLVM_ON_UNIX=1",