runtime/CMakeLists.txt: Always use target triple in ldc2.conf for libdir

Don't use the string "default" in the configuration file for the
native libraries, instead prefer the target
triple (x86_64-.*-linux-gnu for example), similarly to what is done
for the MULTILIB build.

This is done for two reasons:
1. Keeps the filenames consistent as, now, we can name all the config
files 30-ldc-runtime... instead of forcing the native one to be 30 and
all the cross ones to be 31.
2. It allows simpler plug-and-play for cross runtime builds (through
ldc-build-runtime for example) as the configuration file can now be
installed alongside the compiler without its libdirs conflicting with
the native ones.

Signed-off-by: Andrei Horodniceanu <a.horodniceanu@proton.me>

Author: the-horo

runtime/CMakeLists.txt

@@ -268,48 +268,28 @@ elseif(${BUILD_SHARED_LIBS} STREQUAL "OFF")
     list(APPEND switches "-link-defaultlib-shared=false")
 endif()
 
-set(build_libdir "${CMAKE_BINARY_DIR}/lib${LIB_SUFFIX}")
-set(install_libdir "${CMAKE_INSTALL_LIBDIR}")
-
-# Default -rpath linker option when linking against shared libraries.
-if(SHARED_LIBS_SUPPORTED)
-    set(build_rpath   "${build_libdir}")
-    set(install_rpath "${install_libdir}")
-endif()
-
-makeConfSection(NAME "30-ldc-runtime-lib${LIB_SUFFIX}"
-    SECTION "default"
-
-    BUILD
-    SWITCHES ${switches}
-    LIB_DIRS OVERRIDE ${build_libdir}
-    RPATH ${build_rpath}
-
-    INSTALL
-    SWITCHES ${switches}
-    LIB_DIRS OVERRIDE ${install_libdir}
-    RPATH ${install_rpath}
-)
+# comp_args are arguments passed to ldc2 to change the triple
+function(makeTripleConfig comp_args suffix build_libdir install_libdir)
+    set(name "30-ldc-runtime-lib${suffix}")
+    set(sectionPlaceholder "LDC_CONF_MULTILIB_TRIPLE_REGEX")
 
-# macOS has fat libraries; otherwise, append a separate config file section for the
-# multilib target and override the lib directory.
-if(MULTILIB AND NOT "${TARGET_SYSTEM}" MATCHES "APPLE")
-    set(build_libdir "${CMAKE_BINARY_DIR}/lib${MULTILIB_SUFFIX}")
-    set(install_libdir "${CMAKE_INSTALL_PREFIX}/lib${MULTILIB_SUFFIX}")
+    # Default -rpath linker option when linking against shared libraries.
     if(SHARED_LIBS_SUPPORTED)
 	set(build_rpath   "${build_libdir}")
 	set(install_rpath "${install_libdir}")
     endif()
 
-    set(name "31-ldc-runtime-lib${MULTILIB_SUFFIX}")
-    set(sectionPlaceholder "LDC_CONF_MULTILIB_TRIPLE_REGEX")
     makeConfSection(NAME "${name}"
 	SECTION "${sectionPlaceholder}"
+
 	BUILD
+	SWITCHES ${switches}
 	LIB_DIRS OVERRIDE ${build_libdir}
         RPATH ${build_rpath}
+
 	INSTALL
-	LIB_DIRS OVERRIDE ${install_libdir}
+	SWITCHES ${switches}
+	LIB_DIRS ${install_libdir}
         RPATH ${install_rpath}
     )
 
@@ -325,13 +305,13 @@ if(MULTILIB AND NOT "${TARGET_SYSTEM}" MATCHES "APPLE")
 	    "${conf}"
 	    "${sectionPlaceholder}"
 	    # Next arguments are a compiler invocation for the desired triple
-	    "${LDC_EXE_FULL}" -m${MULTILIB_SUFFIX}
+	    "${LDC_EXE_FULL}" ${D_FLAGS} ${comp_args}
 	)
 	if(LDC_EXE)
-	    # We need to get the -m32 target triple but the compiler
-	    # is not built yet. We can't depend on LDC_EXE since that
-	    # would cause a cycle so pass-through the needed commands
-	    # up to the root project and let it run them as POST_BUILD
+	    # We need to get the target triple but the compiler is not
+	    # built yet. We can't depend on LDC_EXE since that would
+	    # cause a cycle so pass-through the needed commands up to
+	    # the root project and let it run them as POST_BUILD
 	    # commands. This avoids adding the config_files as
 	    # transitive dependencies to all compiled D files.
 	    #
@@ -345,6 +325,22 @@ if(MULTILIB AND NOT "${TARGET_SYSTEM}" MATCHES "APPLE")
 	    execute_process(COMMAND ${fill_cmd})
 	endif()
     endforeach()
+
+    set(_ALL_CONF_INSTALL_FILES "${_ALL_CONF_INSTALL_FILES}" PARENT_SCOPE)
+    set(_LDC_POST_BUILD_COMMANDS "${_LDC_POST_BUILD_COMMANDS}" PARENT_SCOPE)
+    set(_LDC_POST_BUILD_BYPRODUCTS "${_LDC_POST_BUILD_BYPRODUCTS}" PARENT_SCOPE)
+endfunction()
+
+set(build_libdir "${CMAKE_BINARY_DIR}/lib${LIB_SUFFIX}")
+set(install_libdir "${CMAKE_INSTALL_LIBDIR}")
+makeTripleConfig("" "${LIB_SUFFIX}" "${build_libdir}" "${install_libdir}")
+
+# macOS has fat libraries; otherwise, append a separate config file section for the
+# multilib target and override the lib directory.
+if(MULTILIB AND NOT "${TARGET_SYSTEM}" MATCHES "APPLE")
+    set(build_libdir "${CMAKE_BINARY_DIR}/lib${MULTILIB_SUFFIX}")
+    set(install_libdir "${CMAKE_INSTALL_PREFIX}/lib${MULTILIB_SUFFIX}")
+    makeTripleConfig("-m${MULTILIB_SUFFIX}" "${MULTILIB_SUFFIX}" "${build_libdir}" "${install_libdir}")
 endif()
 
 if(LDC_EXE)

runtime/ldc-build-runtime.d.in

@@ -175,8 +175,13 @@ void runCMake() {
         args ~= [
             "-DCMAKE_INSTALL_PREFIX=" ~ config.ldcExecutable.dirName.dirName,
             "-DLIB_SUFFIX=" ~ config.installWithSuffix,
-            "-DCONF_INST_DIR=", // don't install/overwrite existing etc/ldc2.conf!
         ];
+	if (config.confPreferDir && hostHasDirConfig) {
+	    // All fine, the config files won't conflict
+	} else {
+	    // don't install/overwrite existing etc/ldc2.conf!
+            args ~= "-DCONF_INST_DIR=";
+	}
     }
     if (config.confPreferDir)       args ~= "-DCONF_PREFER_DIR=ON";