Clean up errors thrown during revel-indexer build
From GitLab pipeline build (Alpine Linux)
291 In file included from /usr/include/bsd/sys/cdefs.h:44,
292 from /usr/include/bsd/string.h:39,
293 from ../indexer.h:29,
294 from ../indexer.cpp:24:
295 /usr/include/sys/cdefs.h:1:2: warning: #warning usage of non-standard #include <sys/cdefs.h> is deprecated [-Wcpp]
296 #warning usage of non-standard #include <sys/cdefs.h> is deprecated
297 ^~~~~~~
298 ../indexer.cpp: In function 'int scan_func(const char*, const stat*, int, FTW*)':
299 ../indexer.cpp:48:28: warning: comparison of integer expressions of different signedness: 'const time_t' {aka 'const long int'} and 'uint64_t' {aka 'long unsigned int'} [-Wsign-compare]
300 if (sb->st_ctim.tv_sec > last_scanned) {
301 ~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~
302 ../indexer.cpp: In function 'bool scan_music_file(int, sqlite3*, index_element)':
303 ../indexer.cpp:121:26: warning: unused parameter 'id' [-Wunused-parameter]
304 bool scan_music_file(int id, sqlite3 *sqldb, const index_element file)
305 ~~~~^~
306 ../indexer.cpp: In function 'void insert_folder(int, sqlite3*, index_element)':
307 ../indexer.cpp:247:24: warning: unused parameter 'id' [-Wunused-parameter]
308 void insert_folder(int id, sqlite3 *sqldb, const index_element folder)
309 ~~~~^~
310 ../indexer.cpp: In function 'int main(int, char**)':
311 ../indexer.cpp:319:12: warning: format '%d' expects argument of type 'int', but argument 2 has type 'uint64_t' {aka 'long unsigned int'} [-Wformat=]
312 printf("total_scanned: %d\n", total_scanned);
313 ^~~~~~~~~~~~~~~~~~~~~ ~~~~~~~~~~~~~
314 [2/2] Linking target revel-indexer.
315 /usr/lib/gcc/x86_64-alpine-linux-musl/8.3.0/../../../../x86_64-alpine-linux-musl/bin/ld: /usr/lib/gcc/x86_64-alpine-linux-musl/8.3.0/../../../../lib/libc.so: warning: This function cannot be safely ported, use getline(3) instead, as it is supported by GNU and POSIX.1-2008.