Memory leak after a syntax error

[ProkopRandacek]

import name alias strings are not freed when the parsing fails.

==144915==ERROR: LeakSanitizer: detected memory leaks

Direct leak of 256 byte(s) in 1 object(s) allocated from:
    #0 0x558e5fa91d39 in malloc (/home/prokop/source/umka-lang/build/umka+0x1c7d39)
    #1 0x558e5fb11bb8 in parseImportItem /home/prokop/source/umka-lang/build/../src/umka_decl.c:719:25
    #2 0x558e5fb115be in parseImport /home/prokop/source/umka-lang/build/../src/umka_decl.c:796:9
    #3 0x558e5fb09230 in parseModule /home/prokop/source/umka-lang/build/../src/umka_decl.c:807:9
    #4 0x558e5fb08a5f in parseProgram /home/prokop/source/umka-lang/build/../src/umka_decl.c:824:22
    #5 0x558e5faf0c54 in compilerCompile /home/prokop/source/umka-lang/build/../src/umka_compiler.c:206:5
    #6 0x558e5fad8531 in umkaCompile /home/prokop/source/umka-lang/build/../src/umka_api.c:107:9
    #7 0x558e5fe2dbf4 in main /home/prokop/source/umka-lang/build/../src/umka.c:169:14
    #8 0x7f5d438632cf  (/usr/lib/libc.so.6+0x232cf) (BuildId: 9c28cfc869012ebbd43cdb0f1eebcd14e1b8bdd8)

SUMMARY: AddressSanitizer: 256 byte(s) leaked in 1 allocation(s).

Code that causes the leak:

import R

[vtereshkov]

Closing as duplicate of #212