remove math library for time string conversion

lib/core/ogs-compat.h

@@ -53,7 +53,6 @@
 #include <stdint.h>
 #include <stdlib.h>
 #include <string.h>
-#include <math.h>
 #include <time.h>
 #include <errno.h>
 #include <arpa/inet.h>

lib/sbi/conv.c

@@ -345,7 +345,11 @@ bool ogs_sbi_time_from_string(ogs_time_t *timestamp, char *str)
 
     memset(&tm, 0, sizeof(tm));
     ogs_strptime(seconds, "%Y-%m-%dT%H:%M:%S%z", &tm);
+#if USE_MATH
     usecs = (ogs_time_t)floor(atof(subsecs) * 1000000.0 + 0.5);
+#else
+    usecs = (ogs_time_t)((atof(subsecs) * 10000000 + 5) / 10);
+#endif
 
     rv = ogs_time_from_gmt(timestamp, &tm, usecs);
     if (rv != OGS_OK) {

lib/sbi/meson.build

@@ -42,7 +42,6 @@ libsbi_inc = include_directories('.')
 
 sbi_cc_flags = ['-DOGS_SBI_COMPILATION']
 
-libm_dep = cc.find_library('m', required : true)
 libgnutls_dep = cc.find_library('gnutls', required : true)
 libnghttp2_dep = dependency('libnghttp2', version: '>=1.18.1')
 libmicrohttpd_dep = dependency('libmicrohttpd', version: '>=0.9.40')
@@ -57,7 +56,6 @@ libsbi = library('ogssbi',
                     libcrypt_dep,
                     libapp_dep,
                     libsbi_openapi_dep,
-                    libm_dep,
                     libgnutls_dep,
                     libnghttp2_dep,
                     libmicrohttpd_dep,
@@ -72,7 +70,6 @@ libsbi_dep = declare_dependency(
                     libcrypt_dep,
                     libapp_dep,
                     libsbi_openapi_dep,
-                    libm_dep,
                     libgnutls_dep,
                     libnghttp2_dep,
                     libmicrohttpd_dep,