CI: add more -Werror-* flags

Error out on all warning cases that we have fixed before to make sure nothing
comes in again.

.cirrus.yml

@@ -14,7 +14,7 @@ task:
   pkginstall_script:
     - pkg install -y groff pkgconf check
   configure_script:
-    - echo "clang -O2 -Wall -Wshadow -Werror=implicit-function-declaration -Werror=deprecated-declarations" > conf-cc
+    - echo "clang -O2 -Wall -Wshadow -Werror=implicit-function-declaration -Werror=deprecated-declarations -Werror=parentheses -Werror=dangling-else -Werror=pointer-sign -Werror=incompatible-library-redeclaration -Werror=empty-body -Werror=pointer-sign" > conf-cc
   compile_script:
     - make ${MAKE_FLAGS} it man
   test_script:

.github/workflows/ccpp.yml

@@ -21,22 +21,23 @@ jobs:
            cc: gcc,
            nroff: nroff,
            utmp: false,
-           cflags: "",
+           cflags: "-Werror=deprecated-declarations",
            makeflags: ""
          }
          - {
            name: gcc-no_obsolete,
            cc: gcc,
            nroff: nroff,
            utmp: false,
-           cflags: "-DDEPRECATED_FUNCTIONS_REMOVED",
+           cflags: "-DDEPRECATED_FUNCTIONS_REMOVED -Werror=deprecated-declarations",
            makeflags: ""
          }
          - {
            name: gcc-utmp,
            cc: gcc,
            nroff: true,
            utmp: true,
+           # no deprecated-declarations here as utmp is deprecated on MacOS and that would break the build
            cflags: "-DDEPRECATED_FUNCTIONS_REMOVED",
            makeflags: "-o qtmp.h"
          }
@@ -45,23 +46,24 @@ jobs:
            cc: clang,
            nroff: nroff,
            utmp: false,
-           cflags: "",
+           cflags: "-Werror=incompatible-library-redeclaration -Werror=deprecated-declarations",
            makeflags: ""
          }
          - {
            name: clang-no_obsolete,
            cc: clang,
            nroff: true,
            utmp: false,
-           cflags: "-DDEPRECATED_FUNCTIONS_REMOVED",
+           cflags: "-DDEPRECATED_FUNCTIONS_REMOVED -Werror=incompatible-library-redeclaration -Werror=deprecated-declarations",
            makeflags: ""
          }
          - {
            name: clang-utmp,
            cc: clang,
            nroff: true,
            utmp: true,
-           cflags: "-DDEPRECATED_FUNCTIONS_REMOVED",
+           # no deprecated-declarations here as utmp is deprecated on MacOS and that would break the build
+           cflags: "-DDEPRECATED_FUNCTIONS_REMOVED -Werror=incompatible-library-redeclaration",
            makeflags: "-o qtmp.h"
          }
 
@@ -81,7 +83,7 @@ jobs:
         OS: ${{ matrix.host }}
 
     - name: configure
-      run: echo "${CC} -O2 -fPIC -Wall -Wshadow -Werror=implicit-function-declaration -Wimplicit-fallthrough ${CFLAGS}" > conf-cc
+      run: echo "${CC} -O2 -fPIC -Wall -Wshadow -Werror=implicit-function-declaration -Werror=parentheses -Werror=dangling-else -Werror=pointer-sign -Werror=pointer-sign ${CFLAGS}" > conf-cc
       env:
         CC: ${{ matrix.config.cc }}
         CFLAGS: ${{ matrix.config.cflags }}