Add ruby 3.0 testing

testflags tweak for C standard > c90

Only add -Wdeclaration-after-statement for > c90 as c99 allows
declarations after a statement.

.travis.yml

@@ -62,7 +62,7 @@ matrix:
       dist: xenial
     - compiler: gcc
       os: linux
-      env: SWIGLANG=go VER=1.12
+      env: SWIGLANG=go VER=1.12 CSTD=gnu99
       dist: xenial
     - compiler: gcc
       os: linux
@@ -276,6 +276,10 @@ matrix:
       os: linux
       env: SWIGLANG=ruby VER=2.7
       dist: xenial
+    - compiler: gcc
+      os: linux
+      env: SWIGLANG=ruby VER=3.0 CSTD=c99
+      dist: xenial
     - compiler: gcc
       os: linux
       env: SWIGLANG=scilab
@@ -369,7 +373,7 @@ matrix:
     - compiler: clang
       os: osx
       osx_image: xcode12.2
-      env: SWIGLANG=go
+      env: SWIGLANG=go CSTD=gnu99
     - compiler: clang
       os: osx
       osx_image: xcode12.2

Tools/testflags.py

@@ -3,11 +3,15 @@
 def get_cflags(language, std, compiler):
     if std == None or len(std) == 0:
         std = "gnu89"
-    c_common = "-fdiagnostics-show-option -std=" + std + " -Wno-long-long -Wreturn-type -Wdeclaration-after-statement -Wmissing-field-initializers"
+    c_common = "-fdiagnostics-show-option -std=" + std + " -Wno-long-long -Wreturn-type -Wmissing-field-initializers"
+    if std == "gnu89" or std == "gnu90":
+        # gnu89 standard allows declaration after headers
+        # use c99 or gnu99 if feature is necessary for using target language
+        c_common = c_common + " -Wdeclaration-after-statement"
     cflags = {
         "csharp":"-Werror " + c_common,
              "d":"-Werror " + c_common,
-            "go":"-Werror " + c_common + " -Wno-declaration-after-statement",
+            "go":"-Werror " + c_common,
          "guile":"-Werror " + c_common,
           "java":"-Werror " + c_common,
     "javascript":"-Werror " + c_common,