Support cross-builds and alternative compilers with GN

Adds GN versions of the gyp_configure targets, to create custom
toolchains we can use to override compilers used by GN.

Change-Id: Ic3a9cb7e83f845180396faff632f72f9c24f3365
Reviewed-by: Michal Klocek <michal.klocek@qt.io>

1 files changed, 29 insertions, 0 deletions

diff --git a/src/buildtools/configure_target.pro b/src/buildtools/configure_target.pro
new file mode 100644
index 000000000..ab30570e0
--- /dev/null
+++ b/src/buildtools/configure_target.pro
@@ -0,0 +1,29 @@
+# Prevent generating a makefile that attempts to create a lib
+TEMPLATE = aux
+
+GN_CPU = $$gnArch($$QT_ARCH)
+GN_OS = $$gnOS()
+
+clang: GN_CLANG = true
+else: GN_CLANG = false
+
+# We always use the gcc_toolchain, because clang_toolchain is just
+# a broken wrapper around it for Google's custom clang binaries.
+GN_CONTENTS = \
+"gcc_toolchain(\"target\") {" \
+"  cc = \"$$which($$QMAKE_CC)\" " \
+"  cxx = \"$$which($$QMAKE_CXX)\" " \
+"  ld = \"$$which($$QMAKE_LINK)\" " \
+"  ar = \"$$which($${CROSS_COMPILE}ar)\" " \
+"  nm = \"$$which($${CROSS_COMPILE}nm)\" " \
+"  toolchain_args = { " \
+"    current_os = \"$$GN_OS\" " \
+"    current_cpu = \"$$GN_CPU\" " \
+"    is_clang = $$GN_CLANG " \
+"  } " \
+"}"
+
+GN_FILE = $$OUT_PWD/../toolchain/BUILD.gn
+!build_pass {
+    write_file($$GN_FILE, GN_CONTENTS, append)
+}