Compile with GCC 10+

[nathanesau]

Re. Goals "Compile with GCC 10+"

• J does compile with GCC 10.2.0 by allowing warnings when compiling, i.e.

# CMakeLists.txt
# add_compile_options($<$<COMPILE_LANGUAGE:C,CXX>:-Werror>)

For reference, the warnings list is here.

# https://pastebin.com/raw/F4fsDiEW
ninja -C build > warnings.txt

About the warnings:

• -Wcast-function-type: 237
• -Wsequence-point: 1
• -Wunused-macros: 6
• Total: 244

If we can come up with a strategy to resolve the warning "cast between incompatible function types", we are basically done.

About my system:

# gcc (GCC) 10.2.0
# Copyright (C) 2020 Free Software Foundation, Inc.
# This is free software; see the source for copying conditions.  There is NO
# warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
gcc --version

# Linux manjaro-linux 5.9.16-1-MANJARO #1 SMP PREEMPT Mon Dec 21 22:00:46 UTC 2020 x86_64 GNU/Linux
uname -a

[juntuu]

We would like to keep -Werror (see #90), so, to get it building there would be two options:

• disable the warning with -fno-<warning>
• exclude the warning from errors with -Wno-error=<warning>

In this case disabling the cast-function-type warning would be better in my opinion, as it is not high priority and would generate lot of warnings.

Also, sequence-point and unused-macros should already be excluded from errors, so those are only warnings.

[Sebanisu]

Last night I pulled main and it wouldn't compile anymore I wonder if this is why. It was late so I couldn't look into it. I'm also using GCC 10.2.