gnu: r-colorout: Adjust GCC@14.

* gnu/packages/cran.scm (r-colorout)[arguments]: New phase that set GCC
compiler flag.

Change-Id: I7616cbd7918e00faed307dcc41dd6fe9cbc02086

gnu/packages/cran.scm

@@ -1833,6 +1833,22 @@ code for possible problems.")
        (sha256
         (base32 "1rsx69wjpa73c6x2hacvvvbzdzxn7wg06gizf97kasjdlb7azmp3"))))
     (build-system r-build-system)
+    (arguments
+     (list
+      #:phases
+      #~(modify-phases %standard-phases
+          (add-before 'install 'relax-c-standard
+            (lambda _
+              ;; XXX FIXME: $HOME/.R/Makevars seems to be the only way to
+              ;; set custom CFLAGS for R?
+              (setenv "HOME" (getcwd))
+              (mkdir-p ".R")
+              (with-directory-excursion ".R"
+                (with-output-to-file "Makevars"
+                  (lambda _
+                    (display (string-append
+                              "CFLAGS=-g -O2"
+                              " -std=gnu17"))))))))))
     (home-page "https://github.com/jalvesaq/colorout")
     (synopsis "Colorize output in the R REPL")
     (description "@code{colorout} is an R package that colorizes R output when