Needs to include stdio.h in nginx/auto/feature for this to work

[kzcabstone]

https://github.com/SpiderLabs/ModSecurity-nginx/blob/2497e6ac654d0b117b9534aa735b757c6b11c84f/config#L15

nginx src version: 1.20.2

When I was trying to compile the nginx connector module, nginx configure was complaining about libmodsecurity not found. Command line I was using:

./configure --with-http_ssl_module --with-threads  --with-compat --add-dynamic-module=/usr/local/opt/ModSecurity-nginx/

I checked nginx/objs/autoconf.err and this is in it

----------------------------------------
checking for ModSecurity library in "/usr/local/opt/ModSecurity/src/.libs/" and "/usr/local/opt/ModSecurity/headers/" (specified by the MODSECURITY_LIB and MODSECURITY_INC env)

objs/autotest.c:6:5: error: implicitly declaring library function 'printf' with type 'int (const char *, ...)' [-Werror,-Wimplicit-function-declaration]
    printf("hello");;
    ^
objs/autotest.c:6:5: note: include the header <stdio.h> or explicitly provide a declaration for 'printf'
1 error generated.
----------
#include <sys/types.h>
#include <unistd.h>
#include <modsecurity/modsecurity.h>

int main(void) {
    printf("hello");;
    return 0;
}

So I think you need to either set $NGX_INCLUDE_UNISTD_H or not use printf

[liudongmiao]

see #275.

[mikelolasagasti]

Found similar issue since some compilation flags changed for Fedora.

With the following standard build command it fails:

./configure --add-dynamic-module=/builddir/build/BUILD/ModSecurity-nginx-1.0.3
(...)
configuring additional dynamic modules
adding module in /builddir/build/BUILD/ModSecurity-nginx-1.0.3
checking for ModSecurity library ... not found
checking for ModSecurity library in /usr/local/modsecurity ... not found
 ./configure: error: ngx_http_modsecurity_module requires the ModSecurity library.

With manually setting MODSECURITY_LIB and MODSECURITY_INC also fails

export MODSECURITY_LIB=/usr/lib64/
export MODSECURITY_INC=/usr/include/modsecurity
./configure --add-dynamic-module=/builddir/build/BUILD/ModSecurity-nginx-1.0.3
(...)
configuring additional dynamic modules
adding module in /builddir/build/BUILD/ModSecurity-nginx-1.0.3
checking for ModSecurity library in "/usr/lib64/" and "/usr/include/modsecurity" (specified by the MODSECURITY_LIB and MODSECURITY_INC env) ... not found
        ./configure: error: ngx_http_modsecurity_module requires the ModSecurity library and MODSECURITY_LIB is defined as "/usr/lib64/" and MODSECURITY_INC (path for modsecurity.h) "/usr/include/modsecurity", but we cannot find ModSecurity there.

Applying patch in #275 works just fine in both cases:

./configure --add-dynamic-module=/builddir/build/BUILD/ModSecurity-nginx-1.0.3
(...)
adding module in /builddir/build/BUILD/ModSecurity-nginx-1.0.3
checking for ModSecurity library in "/usr/lib64/" and "/usr/include/modsecurity" (specified by the MODSECURITY_LIB and MODSECURITY_INC env) ... found
 + ngx_http_modsecurity_module was configured