Subject: [PATCH 1/2] gnu: slim: Fix build failure with GCC-11

From: Brian Cully <[email-masked]>
Date: Fri, 28 Apr 2023 17:25:22 -0400

GCC-11 sniffed out a long-standing bug where a pointer was being tested for a
negative value, which is impossible. Instead, check for NULL, which is how the
error result is actually returned.

See https://github.com/iwamatsu/slim/issues/14 for details.

* gnu/packages/display-managers.scm (slim) [fix-0-pointer-comparison]: new
phase
---
 gnu/packages/display-managers.scm | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/gnu/packages/display-managers.scm b/gnu/packages/display-managers.scm
index b0d388f1bc..c1a08e8553 100644
--- a/gnu/packages/display-managers.scm
+++ b/gnu/packages/display-managers.scm
@@ -475,7 +475,11 @@ (define-public slim
                ;; The build system's logic here is: if "Linux", then
                 ;; "systemd".  Strip that.
                 ""))
-             #t)))
+             #t))
+         (add-before 'configure 'fix-0-pointer-comparison
+           (lambda _
+             (substitute* "panel.cpp"
+               (("WinGC < 0") "WinGC == NULL")))))
        #:configure-flags '("-DUSE_PAM=yes"
                            "-DUSE_CONSOLEKIT=no")
        #:tests? #f))
-- 
2.39.2