Enable caches for linux_x64

kotlin-native/konan/konan.properties

@@ -68,7 +68,8 @@ cacheableTargets.macos_x64 = \
   ios_x64 \
   ios_arm64
 
-cacheableTargets.linux_x64 =
+cacheableTargets.linux_x64 = \
+  linux_x64
 
 cacheableTargets.mingw_x64 =
 
@@ -400,14 +401,15 @@ targetSysRoot.linux_x64 = $gccToolchain.linux_x64/x86_64-unknown-linux-gnu/sysro
 # targetSysroot-relative.
 libGcc.linux_x64 = ../../lib/gcc/x86_64-unknown-linux-gnu/8.3.0
 targetCpu.linux_x64 = x86-64
-clangFlags.linux_x64 = -cc1 -target-cpu $targetCpu.linux_x64 -emit-obj -disable-llvm-optzns -x ir
+clangFlags.linux_x64 = -cc1 -target-cpu $targetCpu.linux_x64 -emit-obj -disable-llvm-optzns -x ir \
+   -ffunction-sections -fdata-sections
 clangNooptFlags.linux_x64 = -O1
-clangOptFlags.linux_x64 = -O3 -ffunction-sections
+clangOptFlags.linux_x64 = -O3
 clangDebugFlags.linux_x64 = -O0
 clangDynamicFlags.linux_x64 = -mrelocation-model pic
 linkerKonanFlags.linux_x64 = -Bstatic -lstdc++ -Bdynamic -ldl -lm -lpthread \
-  --defsym __cxa_demangle=Konan_cxa_demangle
-linkerOptimizationFlags.linux_x64 = --gc-sections
+  --defsym __cxa_demangle=Konan_cxa_demangle --gc-sections
+linkerOptimizationFlags.linux_x64 =
 linkerNoDebugFlags.linux_x64 = -S
 linkerDynamicFlags.linux_x64 = -shared
 dynamicLinker.linux_x64 = /lib64/ld-linux-x86-64.so.2

kotlin-native/runtime/src/main/cpp/StdCppStubs.cpp

@@ -31,7 +31,7 @@ RUNTIME_USED RUNTIME_WEAK extern "C" char* Konan_cxa_demangle(
 }
 
 namespace std {
-void __throw_length_error(const char* __s __attribute__((unused))) {
+RUNTIME_WEAK void __throw_length_error(const char* __s __attribute__((unused))) {
   RuntimeAssert(false, __s);
 }