use absolute builddir

Dockerfile

@@ -15,7 +15,7 @@ RUN mkdir -p /tmp/build/ && \
 RUN cd /tmp/build/ && \
     git clone https://github.com/sergey-dryabzhinsky/nginx-rtmp-module.git
 
-RUN cd /tmp/build/ && \
+RUN cd /tmp/build/${NGINX_VERSION} && \
     ./configure \
         --sbin-path=/usr/local/sbin/nginx \
         --conf-path=/etc/nginx/nginx.conf \
@@ -36,7 +36,7 @@ RUN cd /tmp/build/ && \
         --with-compat \
         --add-module=../nginx-rtmp-module \
         --with-debug\
-        -builddir=${NGINX_VERSION} \
+        -builddir=/tmp/build/${NGINX_VERSION} \
     make -j $(getconf _NPROCESSORS_ONLN) && \
     make install && \
     mkdir /var/lock/nginx && \