Generate PC files for threads and omp variants of the libs

CMakeLists.txt

@@ -431,6 +431,25 @@ install (FILES
          DESTINATION ${CMAKE_INSTALL_LIBDIR}/pkgconfig
          COMPONENT Development)
 
+# pkgconfig files for the threading variants
+if (Threads_FOUND AND NOT WITH_COMBINED_THREADS)
+  set (THREADLIBS "${CMAKE_THREAD_LIBS_INIT}")
+  configure_file (fftw_threads.pc.in fftw3${PREC_SUFFIX}_threads.pc @ONLY)
+  install (FILES
+            ${CMAKE_CURRENT_BINARY_DIR}/fftw3${PREC_SUFFIX}_threads.pc
+           DESTINATION ${CMAKE_INSTALL_LIBDIR}/pkgconfig
+           COMPONENT Development)
+endif ()
+
+if (OPENMP_FOUND)
+  set (OPENMP_CFLAGS "${OpenMP_C_FLAGS}")
+  configure_file (fftw_omp.pc.in fftw3${PREC_SUFFIX}_omp.pc @ONLY)
+  install (FILES
+            ${CMAKE_CURRENT_BINARY_DIR}/fftw3${PREC_SUFFIX}_omp.pc
+           DESTINATION ${CMAKE_INSTALL_LIBDIR}/pkgconfig
+           COMPONENT Development)
+endif ()
+
 # cmake file
 set (FFTW3_LIBRARIES "FFTW3::${fftw3_lib}")
 configure_file (FFTW3Config.cmake.in FFTW3${PREC_SUFFIX}Config.cmake @ONLY)

Makefile.am

@@ -41,7 +41,8 @@ endif
 
 SUBDIRS=support $(GENFFT) kernel simd-support dft rdft reodft api	\
 libbench2 $(CHICKEN_EGG) tests mpi $(DOCDIR) tools m4
-EXTRA_DIST=COPYRIGHT bootstrap.sh CONVENTIONS fftw.pc.in	\
+EXTRA_DIST=COPYRIGHT bootstrap.sh CONVENTIONS fftw.pc.in		\
+fftw_threads.pc.in fftw_omp.pc.in				\
 CMakeLists.txt cmake.config.h.in FFTW3Config.cmake.in		\
 FFTW3ConfigVersion.cmake.in README-perfcnt.md
 
@@ -165,8 +166,27 @@ endif
 
 fftw3@PREC_SUFFIX@.pc: fftw.pc
 	cp -f fftw.pc fftw3@PREC_SUFFIX@.pc
+
+# A separate pkg-config file is installed for each threading variant that is
+# built.  Each one Requires: the base fftw3 package and adds the threaded
+# library plus the threading libraries needed when linking statically.
+if THREADS
+if !COMBINED_THREADS
+THREADS_PC = fftw3@PREC_SUFFIX@_threads.pc
+endif
+endif
+
+if OPENMP
+OPENMP_PC = fftw3@PREC_SUFFIX@_omp.pc
+endif
+
+fftw3@PREC_SUFFIX@_threads.pc: fftw_threads.pc
+	cp -f fftw_threads.pc fftw3@PREC_SUFFIX@_threads.pc
+fftw3@PREC_SUFFIX@_omp.pc: fftw_omp.pc
+	cp -f fftw_omp.pc fftw3@PREC_SUFFIX@_omp.pc
+
 pkgconfigdir = $(libdir)/pkgconfig
-pkgconfig_DATA = fftw3@PREC_SUFFIX@.pc
+pkgconfig_DATA = fftw3@PREC_SUFFIX@.pc $(THREADS_PC) $(OPENMP_PC)
 
 FFTW3@PREC_SUFFIX@Config.cmake: $(top_srcdir)/FFTW3Config.cmake.in
 	$(SED) \

configure.ac

@@ -873,6 +873,8 @@ AC_CONFIG_FILES([
    m4/Makefile
 
    fftw.pc
+   fftw_threads.pc
+   fftw_omp.pc
 ])
 
 AC_OUTPUT

fftw_omp.pc.in

@@ -0,0 +1,12 @@
+prefix=@prefix@
+exec_prefix=@exec_prefix@
+libdir=@libdir@
+includedir=@includedir@
+
+Name: FFTW OpenMP
+Description: fast Fourier transform library, OpenMP variant
+Version: @VERSION@
+Requires: fftw3@PREC_SUFFIX@
+Libs: -L${libdir} -lfftw3@PREC_SUFFIX@_omp
+Libs.private: @OPENMP_CFLAGS@ -lm
+Cflags: -I${includedir}

fftw_threads.pc.in

@@ -0,0 +1,12 @@
+prefix=@prefix@
+exec_prefix=@exec_prefix@
+libdir=@libdir@
+includedir=@includedir@
+
+Name: FFTW threads
+Description: fast Fourier transform library, threaded (pthreads/Win32) variant
+Version: @VERSION@
+Requires: fftw3@PREC_SUFFIX@
+Libs: -L${libdir} -lfftw3@PREC_SUFFIX@_threads
+Libs.private: @THREADLIBS@ -lm
+Cflags: -I${includedir}