Fix Nauty path on Windows

Fix for
SAGE_NAUTY_BINS_PREFIX = "D:\a\_temp\msys64\ucrt64\bin\.EXE"
                             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
SyntaxError: (unicode error) 'unicodeescape' codec can't decode bytes in position 17-19: truncated \uXXXX escape

Author: tobiasdiez

src/sage/config.py.in

@@ -34,8 +34,8 @@ NTL_LIBDIR = "@NTL_LIBDIR@"
 # Path to the ecl-config script
 ECL_CONFIG = "@SAGE_ECL_CONFIG@".replace("${prefix}", SAGE_LOCAL)
 
-# Path to the nauty binaries; of the form "/path/to/" or "/path/to/nauty-" 
-SAGE_NAUTY_BINS_PREFIX = "@SAGE_NAUTY_BINS_PREFIX@"
+# Path to the nauty binaries; of the form "/path/to" or "/path/to/nauty-" 
+SAGE_NAUTY_BINS_PREFIX = r"@SAGE_NAUTY_BINS_PREFIX@"
 
 SAGE_ECMBIN = "@SAGE_ECMBIN@"
 

src/sage/meson.build

@@ -79,7 +79,12 @@ foreach prog : nauty_progs
     )
   endif
   if nauty_check.found()
-    nauty_bins_prefix = nauty_check.full_path().replace(prog, '')
+    nauty_bins_prefix = nauty_check.full_path().replace(prog + '.EXE', '').replace(
+      prog,
+      '',
+    ).strip(
+      '\\/',
+    )
   endif
 endforeach
 conf_data.set('SAGE_NAUTY_BINS_PREFIX', nauty_bins_prefix)