[mono] Fix building multiple os/arch combinations in the same working directory ...

After adding the ICU shim code to the runtime we hit an issue when e.g. compiling for "desktop" mono in a working directory that already had Browser wasm artifacts in it.
This is due to automake putting the intermediate compilation artifacts at the same location where a file was referenced from.

This means that e.g. when using `../../../libraries/Native/Unix/System.Globalization.Native/pal_icushim.c` in the Makefile.am we'd get the intermediaries in `artifacts/obj/mono/libraries/` instead of somewhere in `artifacts/obj/mono/OSX.x64.Debug`.

Later on we'd get the following error because it was reusing the existing .o file from another architecture:

```
Undefined symbols for architecture x86_64:
  "_gPalGlobalizationNative", referenced from:
    _c_qcalls in libmonoruntimesgen.a(libmonoruntimesgen_la-native-library-qcall.o)
```

Fix this by symlinking the source files into the build directory.

diff --git a/src/mono/mono/metadata/Makefile.am b/src/mono/mono/metadata/Makefile.am
index 06abdd5..76fa995 100644 (file)
--- a/src/mono/mono/metadata/Makefile.am
+++ b/src/mono/mono/metadata/Makefile.am
@@ -142,26 +142,31 @@ libmonoruntime_support_la_CFLAGS = $(filter-out @CXX_REMOVE_CFLAGS@, @CFLAGS@) @
 
 if ENABLE_NETCORE
 if HAVE_SYS_ICU
+
+# symlink ICU sources to a local dir so automake puts intermediates into the target-specific folder
+icushim/%.c: @ICU_SHIM_PATH@/%.c
+       $(LN_S) $^ $@
+
 shim_libraries = libmonoruntime-shimglobalization.la
 
 nodist_libmonoruntime_shimglobalization_la_SOURCES = \
-                                                                       @ICU_SHIM_PATH@/pal_calendarData.c \
-                                                                       @ICU_SHIM_PATH@/pal_casing.c \
-                                                                       @ICU_SHIM_PATH@/pal_collation.c \
-                                                                       @ICU_SHIM_PATH@/pal_idna.c \
-                                                                       @ICU_SHIM_PATH@/pal_locale.c \
-                                                                       @ICU_SHIM_PATH@/pal_localeNumberData.c \
-                                                                       @ICU_SHIM_PATH@/pal_localeStringData.c \
-                                                                       @ICU_SHIM_PATH@/pal_normalization.c \
-                                                                       @ICU_SHIM_PATH@/pal_timeZoneInfo.c \
-                                                                       @ICU_SHIM_PATH@/entrypoints.c
+                                                                       icushim/pal_calendarData.c \
+                                                                       icushim/pal_casing.c \
+                                                                       icushim/pal_collation.c \
+                                                                       icushim/pal_idna.c \
+                                                                       icushim/pal_locale.c \
+                                                                       icushim/pal_localeNumberData.c \
+                                                                       icushim/pal_localeStringData.c \
+                                                                       icushim/pal_normalization.c \
+                                                                       icushim/pal_timeZoneInfo.c \
+                                                                       icushim/entrypoints.c
 
 libmonoruntime_shimglobalization_la_CFLAGS = @ICU_CFLAGS@ -I$(top_srcdir)/../libraries/Native/Unix/System.Globalization.Native/ -I$(top_srcdir)/../libraries/Native/Unix/Common/
 
 if STATIC_ICU
-nodist_libmonoruntime_shimglobalization_la_SOURCES += @ICU_SHIM_PATH@/pal_icushim_static.c
+nodist_libmonoruntime_shimglobalization_la_SOURCES += icushim/pal_icushim_static.c
 else
-nodist_libmonoruntime_shimglobalization_la_SOURCES += @ICU_SHIM_PATH@/pal_icushim.c
+nodist_libmonoruntime_shimglobalization_la_SOURCES += icushim/pal_icushim.c
 endif # STATIC_ICU
 
 endif # HAVE_SYS_ICU