lib_common: print dlopen errs as warn

Since the libraries should be bundled, treat the dlopen errors rather
as errors and issue warning. This also occurs eg. on bare debootstraped
Ubuntu system, where basic libraries like libasound2, libdrm and libgl1
are missing but are among those excluded from AppImages.

src/lib_common.cpp

@@ -55,6 +55,8 @@
 #include "lib_common.h"
 #include "utils/color_out.h"
 
+#define MOD_NAME "[lib] "
+
 using namespace std;
 
 struct library_class_info_t {
@@ -192,8 +194,8 @@ void open_all(const char *pattern, list<void *> &libs) {
                 void *handle = dlopen(glob_buf.gl_pathv[i], RTLD_NOW|RTLD_GLOBAL);
                 if (!handle) {
                         char *error = dlerror();
-                        verbose_msg("Library %s opening warning: %s \n", glob_buf.gl_pathv[i],
-                                        error);
+                        MSG(WARNING, "Library %s opening warning: %s \n",
+                            glob_buf.gl_pathv[i], error);
                         char *filename = basename(glob_buf.gl_pathv[i]);
                         if (filename && error) {
                                 lib_errors.emplace(filename, error);