Fallback to uuid for ossp-uuid with meson

The upstream name for the ossp-uuid package / pkg-config file is
"uuid". Many distributions change this to be "ossp-uuid" to not
conflict with e2fsprogs.

This lookup fails on distributions which don't change this name, for
example NixOS / nixpkgs. Both "ossp-uuid" and "uuid" are also checked
in configure.ac.

Author: Wolfgang Walther
Reviewed-by: Nazir Bilal Yavuz, Alvaro Herrera, Peter Eisentraut
Reviewed-by: Tristan Partin
Discussion: https://www.postgresql.org/message-id/ca8f37e1-a2c3-40e2-91f6-59c3d3652ad4@technowledgy.de
Backpatch: 16-, where meson support was added

meson.build

@@ -1423,7 +1423,9 @@ if uuidopt != 'none'
     uuidfunc = 'uuid_to_string'
     uuidheader = 'uuid.h'
   elif uuidopt == 'ossp'
-    uuid = dependency('ossp-uuid', required: false)
+    # In upstream, the package and library is called just 'uuid', but many
+    # distros change it to 'ossp-uuid'.
+    uuid = dependency('ossp-uuid', 'uuid', required: false)
     uuidfunc = 'uuid_export'
     uuidheader = 'uuid.h'
 
@@ -1431,8 +1433,6 @@ if uuidopt != 'none'
     # windows installs neither a pkg-config nor a cmake dependency
     # information. Nor is there another supported uuid implementation
     # available on windows.
-    #
-    # Sometimes the ossp-uuid library is named 'uuid' sometimes 'ossp-uuid'
     if not uuid.found()
       uuid = cc.find_library('ossp-uuid',
         required: false, dirs: test_lib_d,