A few win fixes.

1 files changed, 4 insertions, 2 deletions

diff --git a/mesonbuild/coredata.py b/mesonbuild/coredata.py
index 813d4ad..c12477f 100644
--- a/mesonbuild/coredata.py
+++ b/mesonbuild/coredata.py
@@ -61,8 +61,10 @@ class UserStringOption(UserOption):
     def validate(self, value):
         if not isinstance(value, str):
             raise MesonException('Value "%s" for string option "%s" is not a string.' % (str(newvalue), self.name))
-        if self.name == 'prefix' and not os.path.isabs(value):
-            raise MesonException('Prefix option value \'{0}\' must be an absolute path.'.format(value))
+        if self.name == 'prefix':
+            if not os.path.isabs(value):
+                if len(value) >= 2 and value[1] != ':':
+                    raise MesonException('Prefix option value \'{0}\' must be an absolute path.'.format(value))
         if self.name in ('libdir', 'bindir', 'includedir', 'datadir', 'mandir', 'localedir') \
             and os.path.isabs(value):
             raise MesonException('Option %s must not be an absolute path.' % self.name)