Use individual entries for '-Wl,-rpath-link'

When the '-Wl,-rpath-link' option refers to several folders, we can
either use one single entry, like this:

    -Wl,-rpath-link,/path/to/folder1:/path/to/folder2:/path/to/folder3

...or we can use multiple entries, like this:

    -Wl,-rpath-link,/path/to/folder1
    -Wl,-rpath-link,/path/to/folder2
    -Wl,-rpath-link,/path/to/folder3

Because the '-rpath-link' requires full folder paths, using the one
single entry option can result in a very long argument.

While this shouldn't be a problem, at least *one* toolchain (the latest
version of the Tensilica toolchain for Xtensa processors) segfaults when
using arguments that are too long.

Because other toolchains might be affected and because using multiple
entries instead of a very long one doesn't seem to have any drawback,
this patch changes the arguments building logic to use multiple
'-Wl,-rpath-link' entries.

mesonbuild/compilers/compilers.py

@@ -1297,13 +1297,19 @@ class Compiler:
             # https://sourceware.org/bugzilla/show_bug.cgi?id=16936
             # Not needed on Windows or other platforms that don't use RPATH
             # https://github.com/mesonbuild/meson/issues/1897
-            lpaths = ':'.join([os.path.join(build_dir, p) for p in rpath_paths])
+            #
+            # In addition, this linker option tends to be quite long and some
+            # compilers have trouble dealing with it. That's why we will include
+            # one option per folder, like this:
+            #
+            #   -Wl,-rpath-link,/path/to/folder1 -Wl,-rpath,/path/to/folder2 ...
+            #
+            # ...instead of just one single looooong option, like this:
+            #
+            #   -Wl,-rpath-link,/path/to/folder1:/path/to/folder2:...
+
+            args += ['-Wl,-rpath-link,' + os.path.join(build_dir, p) for p in rpath_paths]
 
-            # clang expands '-Wl,rpath-link,' to ['-rpath-link'] instead of ['-rpath-link','']
-            # This eats the next argument, which happens to be 'ldstdc++', causing link failures.
-            # We can dodge this problem by not adding any rpath_paths if the argument is empty.
-            if lpaths.strip() != '':
-                args += ['-Wl,-rpath-link,' + lpaths]
         return args
 
     def thread_flags(self, env):