Include stdbool.h in some files which use it

Done by manual inspection of the output of this script:
grep -r -l -w "bool\|true\|false" * | grep 'c$\|h$' > has_bool
grep -r -l "stdbool.h" * | grep 'c$\|h$' > has_include
grep -F -x -v -f has_include has_bool
Remove stdbool.h from files which don't need it

Done by manual inspection of the output of this script:
grep -r -l -w "bool\|true\|false" * | grep 'c$\|h$' > has_bool
grep -r -l "stdbool.h" * | grep 'c$\|h$' > has_include
grep -F -x -v -f has_bool has_include
Include stdbool.h in headers which have functions with bool in signature

Done by manual inspecting of the output of this script:
grep -r -l -w "bool" * | grep 'c$' | sed 's/.c$//' > has_bool
grep -r -l -w "stdbool.h" * | grep 'h$' | sed 's/.h$//' > has_include
grep -F -x -v -f has_include has_bool
Merge #927 'Fix stdbool.h usage'