RFR: 8311247: Some cpp files are compiled with -std:c11 flag

[Alexey Ivanov]

On Mon, 3 Jul 2023 17:15:17 GMT, Daniel Jeliński <djelinski at openjdk.org> wrote:

> Please review this patch that configures C++ arguments on build jobs that involve compiling CPP files. As a result of this change, CPP files are compiled with `-std:c++14` command line argument instead of `-std:c11`, which is used when C++ arguments are not configured.
> While at it, I simplified the `java.security.jgss/Lib.gmk` file by moving the additional include directory to `EXTRA_HEADER_DIRS`.
> 
> This patch fixes the following clang warning:
> 
> warning: argument unused during compilation: '-std:c11'
> 
> 
> Microsoft states that [std:c++14 is the default](https://learn.microsoft.com/en-us/cpp/build/reference/std-specify-language-standard-version?view=msvc-170), so there shouldn't be any differences in produced code.
> 
> Testing:
> - verified that after the changes, all CPP files are compiled with `std:c++14` instead of `-std:c11`
> - spot-checked a few `cmdline` files that changed after this patch was applied; the `-std` change was the only difference
> - tier1-5 builds, tier1-2 tests and client libs tests continue to pass on Windows, Linux & MacOS.

make/modules/java.desktop/lib/Awt2dLibraries.gmk line 135:

> 133:     OPTIMIZATION := HIGHEST, \
> 134:     CFLAGS := $(CFLAGS_JDKLIB) $(LIBAWT_CFLAGS), \
> 135:     CXXFLAGS := $(CXXFLAGS_JDKLIB) $(LIBAWT_CFLAGS), \

`LIBAWT_CFLAGS` applies to both C and C++, right? It contains some common flags; it follows the pattern with other libs below.

-------------

PR Review Comment: https://git.openjdk.org/jdk/pull/14758#discussion_r1251253977