Compilation fails with --with-lmdb

[mdunc]

Describe the bug

When compiling with LMDB, compilation fails with an error regarding Regex

Logs and dumps

Output of:
Compilation error:

collection/backend/lmdb.cc: In member function 'virtual void modsecurity::collection::backend::LMDB::resolveRegularExpression(const string&, std::vector<const modsecurity::VariableValue*>*, modsecurity::Variables::KeyExclusions&)':
collection/backend/lmdb.cc:541:38: error: use of deleted function 'modsecurity::Utils::Regex::Regex(const modsecurity::Utils::Regex&)'
     Utils::Regex r = Utils::Regex(var);
                                      ^
In file included from ../src/variables/variable.h:28:0,
                 from ../src/collection/backend/lmdb.h:39,
                 from collection/backend/lmdb.cc:17:
../src/utils/regex.h:57:5: note: declared here
     Regex(const Regex&) = delete;
     ^
Makefile:2608: recipe for target 'collection/backend/libmodsecurity_la-lmdb.lo' failed
make[3]: *** [collection/backend/libmodsecurity_la-lmdb.lo] Error 1
make[3]: Leaving directory '/build/ModSecurity/src'
Makefile:3196: recipe for target 'all-recursive' failed
make[2]: *** [all-recursive] Error 1
make[2]: Leaving directory '/build/ModSecurity/src'
Makefile:1009: recipe for target 'all' failed
make[1]: *** [all] Error 2
make[1]: Leaving directory '/build/ModSecurity/src'
Makefile:1014: recipe for target 'all-recursive' failed
make: *** [all-recursive] Error 1

To Reproduce

Steps to reproduce the behavior:

Easily reproducible in a fresh Ubuntu 16.04 Docker container, but I imagine other distros are also affected.

docker run --rm -ti ubuntu:16.04 bash

#install build dependencies
apt update
apt -y install build-essential git libpcre3-dev libltdl-dev libtool zlib1g-dev autoconf
mkdir /build
cd /build

#compile and install lmdb
git clone https://github.com/LMDB/lmdb.git
cd lmdb/libraries/liblmdb
make && make install && ldconfig

#compile and install ModSecurity
cd /build
git clone https://github.com/SpiderLabs/ModSecurity.git
cd ModSecurity
git checkout v3/master
git submodule init
git submodule update
./build.sh
./configure --with-lmdb
make && make install

Expected behavior

The expected behavior is the compilation completes successfully as it did before.

[mdunc]

If I checkout e0a0fa0, it compiles just fine.

[WGH-]

The fix is simple, I wonder why CI didn't catch this though. I'll check that.