Added C standard gnu23 to the makefile (#288)

* Added C standard gnu23 to the makefile

* Added gnu23 standard to all test modue makefiles

* Added installation of latest gcc version to tests workflow

* Fixed typo in previous commit

* Made GCC 14 installation conditional and moved from the workflow to the script

* Extracted GCC version check to external script for CI and created tests README

* Added #!/bin/bash

* Make check_gcc_version.sh executable

tests/README

@@ -0,0 +1,5 @@
+These are tests that run on the repository's CI or can be run locally 
+to make sure none of the base modules are broken.
+
+The project uses the gnu23 C standard which is stably supported from GCC 14 and onwards 
+so this project should be compiled with GCC 14 or later.

tests/bitset/Makefile

@@ -1,7 +1,7 @@
 
 CC := gcc
 CFLAGS := -I../../include -I. \
-          -g -O3 -Wall -Werror
+          -g -O3 -std=gnu23 -Wall -Werror
 SRC            := bitset_test.c         \
                   ../../source/bitset.c
 OUT            := build/bitset_test 

tests/list/Makefile

@@ -1,7 +1,7 @@
 
 CC := gcc
 CFLAGS := -I../../include -I. \
-          -g -O3 -Wall -Werror -DPOOLS_TEST_ENV=yes
+          -g -O3 -std=gnu23 -Wall -Werror -DPOOLS_TEST_ENV=yes
 
 SRC            := list_test.c          \
                   ../../source/list.c  \

tests/pool/Makefile

@@ -1,7 +1,7 @@
 
 CC := gcc
 CFLAGS := -I../../include -I. \
-          -g -O3 -Wall -Werror -DPOOLS_TEST_ENV=yes
+          -g -O3 -std=gnu23 -Wall -Werror -DPOOLS_TEST_ENV=yes
 
 SRC            := pool_test.c ../../source/pool.c ../../source/bitset.c
 OUT            := build/pool_test 

tests/util/Makefile

@@ -1,7 +1,7 @@
 
 CC := gcc
 CFLAGS := -I../../include -I. \
-          -g -O3 -Wall -Werror -Wno-format
+          -g -O3 -std=gnu23 -Wall -Werror -Wno-format
 
 SRC            := util_test.c ../../source/util.c
 OUT            := build/util_test