gnu: Remove GCC < 7 workarounds.

* gnu/packages/emulators.scm (dolphin-emu)[native-inputs]: Remove GCC-7.
[arguments]: Adjust accordingly.
* gnu/packages/games.scm (openrct2): Likewise.
* gnu/packages/linux.scm (make-linux-libre): Likewise.
* gnu/packages/mpd.scm (mpd): Likewise.
* gnu/packages/storage.scm (ceph): Likewise.

gnu/packages/emulators.scm

@@ -151,11 +151,6 @@
        '(#:tests? #f
          #:phases
          (modify-phases %standard-phases
-           (add-before 'configure 'fixgcc7
-             (lambda _
-               (unsetenv "C_INCLUDE_PATH")
-               (unsetenv "CPLUS_INCLUDE_PATH")
-               #t))
            (add-before 'configure 'generate-fonts&hardcore-libvulkan-path
              (lambda* (#:key inputs outputs #:allow-other-keys)
                (let ((fontfile
@@ -189,7 +184,6 @@
                "-DX11_FOUND=1")))
       (native-inputs
        `(("pkg-config" ,pkg-config)
-         ("gcc" ,gcc-7) ; Building with gcc@5 doesn't work anymore.
          ("gettext" ,gnu-gettext)))
       (inputs
        `(("alsa-lib" ,alsa-lib)

gnu/packages/games.scm

@@ -2615,16 +2615,12 @@ Transport Tycoon Deluxe.")
                                 "/share/openrct2/title-sequences") "data/title")
               (copy-recursively (string-append objects
                                 "/share/openrct2/objects") "data/object"))))
-          (add-before 'configure 'fixgcc7
-             (lambda _
-               (unsetenv "C_INCLUDE_PATH")
-               (unsetenv "CPLUS_INCLUDE_PATH")
-               #t))
-          (add-after 'fixgcc7 'get-rid-of-errors
+          (add-before 'configure 'get-rid-of-errors
             (lambda _
               ;; Don't treat warnings as errors.
               (substitute* "CMakeLists.txt"
-                (("-Werror") "")))))))
+                (("-Werror") ""))
+              #t)))))
     (inputs `(("curl" ,curl)
               ("fontconfig" ,fontconfig)
               ("freetype" ,freetype)
@@ -2640,8 +2636,7 @@ Transport Tycoon Deluxe.")
               ("speexdsp" ,speexdsp)
               ("zlib" ,zlib)))
     (native-inputs
-     `(("gcc" ,gcc-7)
-       ("pkg-config" ,pkg-config)))
+     `(("pkg-config" ,pkg-config)))
     (home-page "https://github.com/OpenRCT2/OpenRCT2")
     (synopsis "Free software re-implementation of RollerCoaster Tycoon 2")
     (description "OpenRCT2 is a free software re-implementation of

gnu/packages/linux.scm

@@ -308,10 +308,6 @@ for ARCH and optionally VARIANT, or #f if there is no such configuration."
        ("flex" ,flex)
        ("bison" ,bison)
 
-       ;; Build with GCC-7 for full retpoline support.
-       ;; FIXME: Remove this when our default compiler has retpoline support.
-       ("gcc" ,gcc-7)
-
        ;; These are needed to compile the GCC plugins.
        ("gmp" ,gmp)
        ("mpfr" ,mpfr)
@@ -338,11 +334,6 @@ for ARCH and optionally VARIANT, or #f if there is no such configuration."
              (substitute* (find-files "." "^Makefile(\\.include)?$")
                (("/bin/pwd") "pwd"))
              #t))
-         (add-before 'configure 'work-around-gcc-7-include-path-issue
-           (lambda _
-             (unsetenv "C_INCLUDE_PATH")
-             (unsetenv "CPLUS_INCLUDE_PATH")
-             #t))
          (replace 'configure
            (lambda* (#:key inputs native-inputs target #:allow-other-keys)
              ;; Avoid introducing timestamps

gnu/packages/mpd.scm

@@ -103,17 +103,7 @@ interfacing MPD in the C, C++ & Objective C languages.")
                 "1ix52vfa8k8my4xyr8b0phg8605b2xchyzyva908m08vpzm14w94"))))
     (build-system meson-build-system)
     (arguments
-     `(#:configure-flags '("-Ddocumentation=true") ; The default is 'false'...
-       #:phases
-       (modify-phases %standard-phases
-         (add-before 'configure 'expand-C++-include-path
-           ;; Make <gcc>/include/c++/ext/string_conversions.h find <stdlib.h>.
-           (lambda* (#:key inputs #:allow-other-keys)
-             (let* ((path "CPLUS_INCLUDE_PATH")
-                    (gcc  (assoc-ref inputs "gcc"))
-                    (c++  (string-append gcc "/include/c++")))
-               (setenv path (string-append c++ ":" (getenv path)))
-               #t))))))
+     `(#:configure-flags '("-Ddocumentation=true"))) ;the default is 'false'...
     (inputs `(("ao" ,ao)
               ("alsa-lib" ,alsa-lib)
               ("avahi" ,avahi)
@@ -135,10 +125,7 @@ interfacing MPD in the C, C++ & Objective C languages.")
               ("pulseaudio" ,pulseaudio)
               ("sqlite" ,sqlite)
               ("zlib" ,zlib)))
-    ;; MPD > 0.21 requires > GCC 6
-    (native-inputs `(("gcc" ,gcc-8)
-                     ("gcc-lib" ,gcc-8 "lib")
-                     ("pkg-config" ,pkg-config)
+    (native-inputs `(("pkg-config" ,pkg-config)
                      ("python-sphinx" ,python-sphinx)))
     ;; Missing optional inputs:
     ;;   libyajl

gnu/packages/storage.scm

@@ -237,11 +237,6 @@
                  (("^add_ceph_test\\(osd-copy-from\\.sh.*$") "\n")
                  (("^add_ceph_test\\(osd-fast-mark-down\\.sh.*$") "\n"))
                #t)))
-         (add-before 'configure 'gcc-workaround
-           (lambda _
-             (unsetenv "C_INCLUDE_PATH")
-             (unsetenv "CPLUS_INCLUDE_PATH")
-             #t))
          (add-before 'check 'set-check-environment
            (lambda _
              ;; Run tests in parallel.
@@ -289,8 +284,7 @@
     (outputs
      '("out" "lib"))
     (native-inputs
-     `(("gcc" ,gcc-7)                      ;7 or later is required
-       ("gperf" ,gperf)
+     `(("gperf" ,gperf)
        ("pkg-config" ,pkg-config)
        ("python-cython" ,python-cython)
        ("python-sphinx" ,python-sphinx)