patch 8.2.0828: Travis: regexp patttern doesn't work everywhere

Problem:    Travis: regexp patttern doesn't work everywhere.
Solution:   Use [:blank:] instead of \b. (Ozaki Kiichi, closes #6146)
diff --git a/.travis.yml b/.travis.yml
index 7c1ecbc..ef96f08 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -125,7 +125,12 @@
       # Append various warning flags to CFLAGS.
       # BSD sed needs backup extension specified.
       sed -i.bak -f ci/config.mk.sed ${SRCDIR}/auto/config.mk
-      sed -i.bak -f ci/config.mk.${CC}.sed ${SRCDIR}/auto/config.mk
+      if [[ "${TRAVIS_OS_NAME}" = "osx" ]]; then
+        # On macOS, the entity of gcc is clang.
+        sed -i.bak -f ci/config.mk.clang.sed ${SRCDIR}/auto/config.mk
+      else
+        sed -i.bak -f ci/config.mk.${CC}.sed ${SRCDIR}/auto/config.mk
+      fi
       make ${SHADOWOPT} -j${NPROC}
     fi
   - echo -en "travis_fold:end:build\\r\\033[0K"
@@ -141,11 +146,10 @@
   - do_test make ${SHADOWOPT} ${TEST} && FOLD_MARKER=travis_fold
   - echo -en "${FOLD_MARKER}:end:test\\r\\033[0K"
 
-
-# instead of a 2*2*8 matrix (2*os + 2*compiler + 8*env),
-# exclude some builds on mac os x and linux
-# on mac os x "tiny" is always without GUI
-# linux: 2*compiler + 5*env + mac: 2*compiler + 2*env
+# Instead of using all environments with both compilers on both systems,
+# exclude some builds on mac os x and linux.
+# On mac os x "tiny" is always without GUI, use 2 compilers in 2 environments.
+# Linux: 2 compilers on some of the environments + gcc on os390
 jobs:
   include:
     - <<: *osx
diff --git a/ci/config.mk.clang.sed b/ci/config.mk.clang.sed
index 40c6705..da6044d 100644
--- a/ci/config.mk.clang.sed
+++ b/ci/config.mk.clang.sed
@@ -1 +1,2 @@
-/^RUBY_CFLAGS\b/s/$/ -Wno-error=unknown-attributes -Wno-error=ignored-attributes/
+/^CFLAGS[[:blank:]]*=/s/$/ -Wno-error=missing-field-initializers/
+/^RUBY_CFLAGS[[:blank:]]*=/s/$/ -Wno-error=unknown-attributes -Wno-error=ignored-attributes/
diff --git a/ci/config.mk.gcc.sed b/ci/config.mk.gcc.sed
index 3b11569..f46e488 100644
--- a/ci/config.mk.gcc.sed
+++ b/ci/config.mk.gcc.sed
@@ -1 +1 @@
-/^CFLAGS\b/s/$/ -Wno-error=maybe-uninitialized/
+/^CFLAGS[[:blank:]]*=/s/$/ -Wno-error=maybe-uninitialized/
diff --git a/ci/config.mk.sed b/ci/config.mk.sed
index 3168278..cd2cd9c 100644
--- a/ci/config.mk.sed
+++ b/ci/config.mk.sed
@@ -1,2 +1,2 @@
-/^CFLAGS\b/s/$/ -Wall -Wextra -Wshadow -Werror/
-/^PERL_CFLAGS\b/s/$/ -Wno-error=unused-function/
+/^CFLAGS[[:blank:]]*=/s/$/ -Wall -Wextra -Wshadow -Werror/
+/^PERL_CFLAGS[[:blank:]]*=/s/$/ -Wno-error=unused-function/
diff --git a/src/if_ruby.c b/src/if_ruby.c
index e989c01..6773a2a 100644
--- a/src/if_ruby.c
+++ b/src/if_ruby.c
@@ -100,7 +100,8 @@
 #endif
 
 // On macOS pre-installed Ruby defines "SIZEOF_TIME_T" as "SIZEOF_LONG" so it
-// conflicts with the definition in config.h then causes macro-redifned warning.
+// conflicts with the definition in config.h then causes a macro-redefined
+// warning.
 #ifdef SIZEOF_TIME_T
 # undef SIZEOF_TIME_T
 #endif
@@ -113,6 +114,11 @@
 # include <st.h>  // for ST_STOP and ST_CONTINUE
 #endif
 
+// See above.
+#ifdef SIZEOF_TIME_T
+# undef SIZEOF_TIME_T
+#endif
+
 #undef off_t	// ruby defines off_t as _int64, Mingw uses long
 #undef EXTERN
 #undef _
diff --git a/src/version.c b/src/version.c
index 8a94dde..c2cb3ca 100644
--- a/src/version.c
+++ b/src/version.c
@@ -747,6 +747,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    828,
+/**/
     827,
 /**/
     826,