Integrated a few external musrfit plug-ins into the standard build process.

In order to enable building of the additional libraries supply the following options to the configure script:

--enable-BMWlibs (for libTFitPofB libLFRelaxation libGapIntegrals libCalcMeanFieldsLEM)
--enable-ASlibs (for libPNL_PippardFitter)

By default, both options are disabled.

At the moment I have tested it only in an SL5 32-bit environment.
Further tests are going to follow.

For a clean installation I suggest to remove any musrfit and plug-in installations before newly building musrfit.

src/external/libCalcMeanFieldsLEM/Makefile.am

@@ -0,0 +1,40 @@
+## Process this file with automake to create Makefile.in
+
+h_sources = \
+  TCalcMeanFieldsLEM.h
+
+h_linkdef = \
+  TCalcMeanFieldsLEMLinkDef.h
+
+dict_h_sources = \
+  TCalcMeanFieldsLEMDict.h
+
+cpp_sources = \
+  TCalcMeanFieldsLEM.cpp
+
+dict_cpp_sources = \
+  TCalcMeanFieldsLEMDict.cpp
+
+include_HEADERS = $(h_sources)
+noinst_HEADERS = $(h_linkdef) $(dict_h_sources)
+
+INCLUDES = -I$(top_srcdir)/src/include $(TFITPOFB_CFLAGS) $(PMUSR_CFLAGS) $(ROOT_CFLAGS)
+AM_CXXFLAGS = $(LOCAL_LIB_CXXFLAGS)
+
+BUILT_SOURCES = $(dict_cpp_sources) $(dict_h_sources)
+AM_LDFLAGS = $(LOCAL_LIB_LDFLAGS) -L@ROOTLIBDIR@
+CLEANFILES = *Dict.cpp *Dict.h *~ core
+
+%Dict.cpp %Dict.h: %.h %LinkDef.h
+	@ROOTCINT@ -v -f $*Dict.cpp -c -p $(INCLUDES) $^
+
+lib_LTLIBRARIES = libCalcMeanFieldsLEM.la
+
+libCalcMeanFieldsLEM_la_SOURCES = $(h_sources) $(cpp_sources) $(dict_h_sources) $(dict_cpp_sources)
+libCalcMeanFieldsLEM_la_LIBADD = $(TFITPOFB_LIBS) $(PMUSR_LIBS) $(ROOT_LIBS)
+libCalcMeanFieldsLEM_la_LDFLAGS = -version-info $(PLUGIN_LIBRARY_VERSION) -release $(PLUGIN_RELEASE) $(AM_LDFLAGS)
+
+## For the moment do not build pkgconfig files for musrfit plug-ins...
+## pkgconfigdir = $(libdir)/pkgconfig
+## pkgconfig_DATA = CalcMeanFieldsLEM.pc
+