dl: add `get_libname` function (#8909)

vlib/dl/dl.v

@@ -7,6 +7,7 @@ pub const (
 
 // get_shared_library_extension returns the platform dependent shared library extension
 // i.e. .dll on windows, .so on most unixes, .dylib on macos.
+[inline]
 pub fn get_shared_library_extension() string {
 	mut res := '.so'
 	$if macos {
@@ -17,3 +18,10 @@ pub fn get_shared_library_extension() string {
 	}
 	return res
 }
+
+// get_libname returns a library name with the operating system specific extension for
+// shared libraries.
+[inline]
+pub fn get_libname(libname string) string {
+	return '$libname$dl.dl_ext'
+}

vlib/dl/dl_nix.c.v

@@ -1,6 +1,7 @@
 module dl
 
 #include <dlfcn.h>
+
 pub const (
 	rtld_now  = C.RTLD_NOW
 	rtld_lazy = C.RTLD_LAZY

vlib/dl/example/use.v

@@ -6,7 +6,7 @@ import dl
 type FNAdder = fn (int, int) int
 
 fn main() {
-	library_file_path := os.join_path(os.getwd(), 'library$dl.dl_ext')
+	library_file_path := os.join_path(os.getwd(), dl.get_libname('library'))
 	handle := dl.open(library_file_path, dl.rtld_lazy)
 	eprintln('handle: ${ptr_str(handle)}')
 	mut f := &FNAdder(0)

vlib/dl/example/use_test.v

@@ -7,7 +7,7 @@ const (
 	vexe              = os.real_path(os.getenv('VEXE'))
 	cfolder           = os.dir(@FILE)
 	so_ext            = dl.dl_ext
-	library_file_name = os.join_path(cfolder, 'library$so_ext')
+	library_file_name = os.join_path(cfolder, dl.get_libname('library'))
 )
 
 fn test_vexe() {