Set gn use_gold based on qmake's use_gold_linker

Avoids adding --use-ld=gold on the link command line when gold linker
has been deselected in Qt.

Change-Id: I2d34cd3043aa24dca1f5f1604c97d8beccb70093
Reviewed-by: Joerg Bornemann <joerg.bornemann@qt.io>

src/buildtools/configure_host.pro

@@ -11,6 +11,9 @@ GN_OS = $$gnOS()
 clang: GN_CLANG = true
 else: GN_CLANG = false
 
+use_gold_linker: GN_USE_GOLD=true
+else: GN_USE_GOLD=false
+
 GN_V8_HOST_CPU = $$GN_HOST_CPU
 contains(GN_TARGET_CPU, "arm")|contains(GN_TARGET_CPU, "mips")|contains(GN_TARGET_CPU, "x86") {
     # The v8 snapshot need a host that matches bitwidth, so we build makesnapshot to 32-bit variants of host.
@@ -33,6 +36,8 @@ GN_CONTENTS = \
 "  toolchain_args = { " \
 "    current_os = \"$$GN_OS\" " \
 "    current_cpu = \"$$GN_HOST_CPU\" " \
+"    is_clang = $$GN_CLANG " \
+"    use_gold = $$GN_USE_GOLD " \
 "  } " \
 "}" \
 "gcc_toolchain(\"v8_snapshot\") {" \
@@ -45,6 +50,8 @@ GN_CONTENTS = \
 "    current_os = \"$$GN_OS\" " \
 "    current_cpu = \"$$GN_V8_HOST_CPU\" " \
 "    v8_current_cpu = \"$$GN_TARGET_CPU\" " \
+"    is_clang = $$GN_CLANG " \
+"    use_gold = $$GN_USE_GOLD " \
 "  } " \
 " } "
 

src/buildtools/configure_target.pro

@@ -7,6 +7,9 @@ GN_OS = $$gnOS()
 clang: GN_CLANG = true
 else: GN_CLANG = false
 
+use_gold_linker: GN_USE_GOLD=true
+else: GN_USE_GOLD=false
+
 GN_CONTENTS = \
 "gcc_toolchain(\"target\") {" \
 "  cc = \"$$which($$QMAKE_CC)\" " \
@@ -18,6 +21,7 @@ GN_CONTENTS = \
 "    current_os = \"$$GN_OS\" " \
 "    current_cpu = \"$$GN_CPU\" " \
 "    is_clang = $$GN_CLANG " \
+"    use_gold = $$GN_USE_GOLD " \
 "  } " \
 "}"