Build fails with clang 18.1.3

[karthikr]

[4/55] Compiling C object libcper-parse.so.0.1.p/json-schema.c.o
FAILED: libcper-parse.so.0.1.p/json-schema.c.o 
clang-18 -Ilibcper-parse.so.0.1.p -I. -I.. -I/usr/include/json-c -fdiagnostics-color=never -D_FILE_OFFSET_BITS=64 -Wall -Winvalid-pch -Wextra -Wpedantic -Werror -std=c18 -Og -g '-DLIBCPER_JSON_SPEC="/home/krajagopalan/_ci/libcper/specification/json/cper-json.json"' -D_POSIX_C_SOURCE=200809L -fPIC -Wno-address-of-packed-member -MD -MQ libcper-parse.so.0.1.p/json-schema.c.o -MF libcper-parse.so.0.1.p/json-schema.c.o.d -o libcper-parse.so.0.1.p/json-schema.c.o -c ../json-schema.c
In file included from ../json-schema.c:15:
../json-schema.h:17:34: error: a function declaration without a prototype is deprecated in all versions of C [-Werror,-Wstrict-prototypes]
   17 | void validate_schema_debug_enable();
      |                                  ^
      |                                   void
../json-schema.h:18:35: error: a function declaration without a prototype is deprecated in all versions of C [-Werror,-Wstrict-prototypes]
   18 | void validate_schema_debug_disable();
      |                                   ^
      |                                    void
../json-schema.c:415:34: error: a function declaration without a prototype is deprecated in all versions of C [-Werror,-Wstrict-prototypes]
  415 | void validate_schema_debug_enable()
      |                                  ^
      |                                   void
../json-schema.c:419:35: error: a function declaration without a prototype is deprecated in all versions of C [-Werror,-Wstrict-prototypes]
  419 | void validate_schema_debug_disable()
      |                                   ^
      |                                    void
4 errors generated.
[9/55] Compiling C object libcper-generate.so.0.1.p/generator_cper-generate.c.o
FAILED: libcper-generate.so.0.1.p/generator_cper-generate.c.o 
clang-18 -Ilibcper-generate.so.0.1.p -I. -I.. -I/usr/include/json-c -fdiagnostics-color=never -D_FILE_OFFSET_BITS=64 -Wall -Winvalid-pch -Wextra -Wpedantic -Werror -std=c18 -Og -g '-DLIBCPER_JSON_SPEC="/home/krajagopalan/_ci/libcper/specification/json/cper-json.json"' -D_POSIX_C_SOURCE=200809L -fPIC -MD -MQ libcper-generate.so.0.1.p/generator_cper-generate.c.o -MF libcper-generate.so.0.1.p/generator_cper-generate.c.o.d -o libcper-generate.so.0.1.p/generator_cper-generate.c.o -c ../generator/cper-generate.c
In file included from ../generator/cper-generate.c:11:
../generator/gen-utils.h:21:17: error: a function declaration without a prototype is deprecated in all versions of C [-Werror,-Wstrict-prototypes]
   21 | void init_random();
      |                 ^
      |                  void
1 error generated.
[10/55] Compiling C object libcper-generate.so.0.1.p/generator_gen-utils.c.o
FAILED: libcper-generate.so.0.1.p/generator_gen-utils.c.o 
clang-18 -Ilibcper-generate.so.0.1.p -I. -I.. -I/usr/include/json-c -fdiagnostics-color=never -D_FILE_OFFSET_BITS=64 -Wall -Winvalid-pch -Wextra -Wpedantic -Werror -std=c18 -Og -g '-DLIBCPER_JSON_SPEC="/home/krajagopalan/_ci/libcper/specification/json/cper-json.json"' -D_POSIX_C_SOURCE=200809L -fPIC -MD -MQ libcper-generate.so.0.1.p/generator_gen-utils.c.o -MF libcper-generate.so.0.1.p/generator_gen-utils.c.o.d -o libcper-generate.so.0.1.p/generator_gen-utils.c.o -c ../generator/gen-utils.c
In file included from ../generator/gen-utils.c:9:
../generator/gen-utils.h:21:17: error: a function declaration without a prototype is deprecated in all versions of C [-Werror,-Wstrict-prototypes]
   21 | void init_random();
      |                 ^
      |                  void
../generator/gen-utils.c:45:17: error: a function declaration without a prototype is deprecated in all versions of C [-Werror,-Wstrict-prototypes]
   45 | void init_random()
      |                 ^
      |                  void
2 errors generated.
[19/55] Compiling C object libcper-generate.so.0.1.p/generator_sections_gen-section-ccix-per.c.o
FAILED: libcper-generate.so.0.1.p/generator_sections_gen-section-ccix-per.c.o 
clang-18 -Ilibcper-generate.so.0.1.p -I. -I.. -I/usr/include/json-c -fdiagnostics-color=never -D_FILE_OFFSET_BITS=64 -Wall -Winvalid-pch -Wextra -Wpedantic -Werror -std=c18 -Og -g '-DLIBCPER_JSON_SPEC="/home/krajagopalan/_ci/libcper/specification/json/cper-json.json"' -D_POSIX_C_SOURCE=200809L -fPIC -MD -MQ libcper-generate.so.0.1.p/generator_sections_gen-section-ccix-per.c.o -MF libcper-generate.so.0.1.p/generator_sections_gen-section-ccix-per.c.o.d -o libcper-generate.so.0.1.p/generator_sections_gen-section-ccix-per.c.o -c ../generator/sections/gen-section-ccix-per.c
In file included from ../generator/sections/gen-section-ccix-per.c:9:
../generator/sections/../gen-utils.h:21:17: error: a function declaration without a prototype is deprecated in all versions of C [-Werror,-Wstrict-prototypes]
   21 | void init_random();
      |                 ^
      |                  void
1 error generated.
[24/55] Compiling C object libcper-generate.so.0.1.p/generator_sections_gen-section-arm.c.o
FAILED: libcper-generate.so.0.1.p/generator_sections_gen-section-arm.c.o 
clang-18 -Ilibcper-generate.so.0.1.p -I. -I.. -I/usr/include/json-c -fdiagnostics-color=never -D_FILE_OFFSET_BITS=64 -Wall -Winvalid-pch -Wextra -Wpedantic -Werror -std=c18 -Og -g '-DLIBCPER_JSON_SPEC="/home/krajagopalan/_ci/libcper/specification/json/cper-json.json"' -D_POSIX_C_SOURCE=200809L -fPIC -MD -MQ libcper-generate.so.0.1.p/generator_sections_gen-section-arm.c.o -MF libcper-generate.so.0.1.p/generator_sections_gen-section-arm.c.o.d -o libcper-generate.so.0.1.p/generator_sections_gen-section-arm.c.o -c ../generator/sections/gen-section-arm.c
In file included from ../generator/sections/gen-section-arm.c:10:
../generator/sections/../gen-utils.h:21:17: error: a function declaration without a prototype is deprecated in all versions of C [-Werror,-Wstrict-prototypes]
   21 | void init_random();
      |                 ^
      |                  void
../generator/sections/gen-section-arm.c:14:30: error: a function declaration without a prototype is deprecated in all versions of C [-Werror,-Wstrict-prototypes]
   14 | void *generate_arm_error_info();
      |                              ^
      |                               void
../generator/sections/gen-section-arm.c:85:30: error: a function declaration without a prototype is deprecated in all versions of C [-Werror,-Wstrict-prototypes]
   85 | void *generate_arm_error_info()
      |                              ^
      |                               void
3 errors generated.
[29/55] Compiling C object libcper-parse.so.0.1.p/sections_cper-section-arm.c.o
ninja: build stopped: subcommand failed.

[edtanous]

Clang 18 is tested as part of CI. Not clear why this is different.