Kill bashizm

'=' operator for test(1) is not portable.
Merge branch 'hotfix-kill-bashism-2nd' into release-1.4
Update NEWS
Update ChangeLog
Bump version
Merge branch 'develop' into release-1.4
Checks the availability of some C compiler warning flags
Merge branch 'hotfix-test-compiler-flags' into release-1.4
Merge branch 'fix-for-no-long-option-build' into release-1.4
Merge branch 'develop' into release-1.4
Build fix for Interix
Check strdup availability
Add support for strdup-missing environments
Merge branch 'release-1.4' into hotfix-portable-strdup
Add definition _ALL_SOURCES for some platforms
Don't use -C option of make command, for the portability
Merge branch 'release-1.4' into hotfix-portable-test
Don't use shell-builtin '!'
Merge branch 'hotfix-portable-test' into release-1.4
Merge branch 'hotfix-portable-strdup' into release-1.4