ncarg @6.6.2_2: regression, library not found for -lgomp

[Dave-Allured (Dave Allured)]

As of 2020 Feb 6, the default variant of ncarg fails to build from source under at least some conditions. A regresson in Portfile @6.6.2_2, last modified January 17, seems likely. Compile goes well, then breaks when linking the main executable "ncl".

• Mac OS 10.14.6, Mojave
• Xcode 11.3
• Macports 2.6.2
• Using custom prefix in user home, not /opt/local.

Command history, simplified:

port install gcc9
port install hdf5 +gcc9
port install ncarg

Main.log, lines 46904-46907:

:info:build ld: warning: directory not found for option '-L/Volumes/User/dallured/port/262/var/macports/build/_Volumes_User_dallured_port_262_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_science_ncarg/ncarg/work/destroot/Users/dallured/port/262/lib'
:info:build ld: library not found for -lgomp
:info:build clang: error: linker command failed with exit code 1 (use -v to see invocation)
:info:build make[4]: *** [ncl] Error 1

This commit of January 17 ​https://github.com/macports/macports-ports/commit/b63f838f39ee45178d3ffcbbbd36050e8e7f436c seems to be the problem.

Reverting to the previous portfile version of January 6 ​https://github.com/macports/macports-ports/blob/86f87e9d7727ee70b7e35a91d940104640580740/science/ncarg/Portfile builds correctly.

[Dave-Allured (Dave Allured)]

Main.log, Feb. 5, ncarg, library not found for -lgomp

[tenomoto (Takeshi Enomoto)]

In 5ecfbb9005abe69cf5c18f03426d66d309e68202/macports-ports (master):

ncarg: fix a link error

• correctly set C++ compiler in ${configure.cxx}
• provide the absolute path to libgomp.dylib

Closes: #60054