Hi!
Thanks for the answer.

This is what i get from g++ (a little bit long, sorry about that):
-----
/usr/local/lib/libraw.a(lib_libraw_a-dcraw_common.o): In function `_ZN6LibRaw15ahd_interpolateEv.omp_fn.0':
.../Software/Libraries/LibRaw-0.12.1/internal/dcraw_common.cpp:4178: undefined reference to `GOMP_loop_dynamic_start'
.../Software/Libraries/LibRaw-0.12.1/internal/dcraw_common.cpp:4166: undefined reference to `omp_get_thread_num'
.../Software/Libraries/LibRaw-0.12.1/internal/dcraw_common.cpp:4178: undefined reference to `GOMP_loop_dynamic_next'
.../Software/Libraries/LibRaw-0.12.1/internal/dcraw_common.cpp:4192: undefined reference to `GOMP_loop_end'
/usr/local/lib/libraw.a(lib_libraw_a-dcraw_common.o): In function `LibRaw::ahd_interpolate()':
.../Software/Libraries/LibRaw-0.12.1/internal/dcraw_common.cpp:4166: undefined reference to `GOMP_parallel_start'
.../Software/Libraries/LibRaw-0.12.1/internal/dcraw_common.cpp:4166: undefined reference to `GOMP_parallel_end'
/usr/local/lib/libraw.a(lib_libraw_a-dcraw_common.o): In function `_ZN6LibRaw15ppg_interpolateEv.omp_fn.1':
.../Software/Libraries/LibRaw-0.12.1/internal/dcraw_common.cpp:3861: undefined reference to `omp_get_num_threads'
.../Software/Libraries/LibRaw-0.12.1/internal/dcraw_common.cpp:3861: undefined reference to `omp_get_thread_num'
/usr/local/lib/libraw.a(lib_libraw_a-dcraw_common.o): In function `_ZN6LibRaw15ppg_interpolateEv.omp_fn.2':
.../Software/Libraries/LibRaw-0.12.1/internal/dcraw_common.cpp:3883: undefined reference to `omp_get_num_threads'
.../Software/Libraries/LibRaw-0.12.1/internal/dcraw_common.cpp:3883: undefined reference to `omp_get_thread_num'
/usr/local/lib/libraw.a(lib_libraw_a-dcraw_common.o): In function `_ZN6LibRaw15ppg_interpolateEv.omp_fn.3':
.../Software/Libraries/LibRaw-0.12.1/internal/dcraw_common.cpp:3897: undefined reference to `omp_get_num_threads'
.../Software/Libraries/LibRaw-0.12.1/internal/dcraw_common.cpp:3897: undefined reference to `omp_get_thread_num'
/usr/local/lib/libraw.a(lib_libraw_a-dcraw_common.o): In function `LibRaw::ppg_interpolate()':
.../Software/Libraries/LibRaw-0.12.1/internal/dcraw_common.cpp:3858: undefined reference to `GOMP_parallel_start'
.../Software/Libraries/LibRaw-0.12.1/internal/dcraw_common.cpp:3858: undefined reference to `GOMP_parallel_end'
.../Software/Libraries/LibRaw-0.12.1/internal/dcraw_common.cpp:3880: undefined reference to `GOMP_parallel_start'
.../Software/Libraries/LibRaw-0.12.1/internal/dcraw_common.cpp:3880: undefined reference to `GOMP_parallel_end'
.../Software/Libraries/LibRaw-0.12.1/internal/dcraw_common.cpp:3894: undefined reference to `GOMP_parallel_start'
.../Software/Libraries/LibRaw-0.12.1/internal/dcraw_common.cpp:3894: undefined reference to `GOMP_parallel_end'
/usr/local/lib/libraw.a(lib_libraw_a-dcraw_common.o): In function `_ZN6LibRaw15wavelet_denoiseEv.omp_fn.4':
.../Software/Libraries/LibRaw-0.12.1/internal/dcraw_common.cpp:3313: undefined reference to `omp_get_num_threads'
.../Software/Libraries/LibRaw-0.12.1/internal/dcraw_common.cpp:3313: undefined reference to `omp_get_thread_num'
.../Software/Libraries/LibRaw-0.12.1/internal/dcraw_common.cpp:3319: undefined reference to `GOMP_barrier'
.../Software/Libraries/LibRaw-0.12.1/internal/dcraw_common.cpp:3326: undefined reference to `GOMP_barrier'
.../Software/Libraries/LibRaw-0.12.1/internal/dcraw_common.cpp:3334: undefined reference to `GOMP_barrier'
.../Software/Libraries/LibRaw-0.12.1/internal/dcraw_common.cpp:3343: undefined reference to `GOMP_barrier'
.../Software/Libraries/LibRaw-0.12.1/internal/dcraw_common.cpp:3355: undefined reference to `GOMP_barrier'
/usr/local/lib/libraw.a(lib_libraw_a-dcraw_common.o): In function `LibRaw::wavelet_denoise()':
.../Software/Libraries/LibRaw-0.12.1/internal/dcraw_common.cpp:3313: undefined reference to `GOMP_parallel_start'
.../Software/Libraries/LibRaw-0.12.1/internal/dcraw_common.cpp:3313: undefined reference to `GOMP_parallel_end'
collect2: ld returned 1 exit status
-----

I don't really know why the compiler looks for this file, because is not even in the /usr/local/lib or /usr/local/include directories.

I hope this could give you relevant information in order to point me in the right direction.

Thanks in advance!.