Fix link with jansson (#63)

jansson/lib/libjansson.a(value.o): In function `json_real':
value.c:(.text+0x3134): undefined reference to `__isnan'
value.c:(.text+0x314c): undefined reference to `__isinf'
jansson/lib/libjansson.a(value.o): In function `json_real_set':
value.c:(.text+0x3294): undefined reference to `__isnan'
value.c:(.text+0x32ac): undefined reference to `__isinf'
collect2: error: ld returned 1 exit status

Co-authored-by: Josh McCullough <JoshMcCullough@users.noreply.github.com>

Author: orgads

config

@@ -2,6 +2,6 @@ ngx_module_type=HTTP
 ngx_addon_name=ngx_http_auth_jwt_module
 ngx_module_name=$ngx_addon_name
 ngx_module_srcs="${ngx_addon_dir}/src/ngx_http_auth_jwt_binary_converters.c ${ngx_addon_dir}/src/ngx_http_auth_jwt_header_processing.c ${ngx_addon_dir}/src/ngx_http_auth_jwt_string.c ${ngx_addon_dir}/src/ngx_http_auth_jwt_module.c"
-ngx_module_libs="-ljansson -ljwt"
+ngx_module_libs="-ljansson -ljwt -lm"
 
 . auto/module