stage1: better value for builtin.link_mode

Now it is Dynamic unless -DZIG_STATIC=on is passed to cmake.

This partially addresses #6469.

CMakeLists.txt

@@ -63,6 +63,9 @@ endif()
 
 if(ZIG_STATIC)
     set(ZIG_STATIC_LLVM "on")
+    set(ZIG_LINK_MODE "Static")
+else()
+    set(ZIG_LINK_MODE "Dynamic")
 endif()
 
 string(REGEX REPLACE "\\\\" "\\\\\\\\" ZIG_LIBC_LIB_DIR_ESCAPED "${ZIG_LIBC_LIB_DIR}")

src/stage1/codegen.cpp

@@ -8815,7 +8815,7 @@ Buf *codegen_generate_builtin_source(CodeGen *g) {
     buf_append_str(contents, "/// Deprecated: use `std.Target.current.cpu.arch.endian()`\n");
     buf_append_str(contents, "pub const endian = Target.current.cpu.arch.endian();\n");
     buf_appendf(contents, "pub const output_mode = OutputMode.Obj;\n");
-    buf_appendf(contents, "pub const link_mode = LinkMode.Static;\n");
+    buf_appendf(contents, "pub const link_mode = LinkMode.%s;\n", ZIG_LINK_MODE);
     buf_appendf(contents, "pub const is_test = false;\n");
     buf_appendf(contents, "pub const single_threaded = %s;\n", bool_to_str(g->is_single_threaded));
     buf_appendf(contents, "pub const abi = Abi.%s;\n", cur_abi);

src/stage1/config.h.in

@@ -21,5 +21,6 @@
 #define ZIG_CLANG_LIBRARIES "@CLANG_LIBRARIES@"
 #define ZIG_LLVM_CONFIG_EXE "@LLVM_CONFIG_EXE@"
 #define ZIG_DIA_GUIDS_LIB "@ZIG_DIA_GUIDS_LIB_ESCAPED@"
+#define ZIG_LINK_MODE "@ZIG_LINK_MODE@"
 
 #endif