CONFIG: update c++ standard, some compiler rules (partially addresses #2209)

- migrate to c++14 for most compilers *except* gcc.
  There are still many systems in use with gcc-4.8.5, which does not
  support c++14.

- initial rules for nvidia compilers (pgi is will soon be defunct).
  Not fully tested...

CONFIG: provide fallback value for the user directory name

- in containers may have an unset USER env variable.
  Default to 'user' to prevent ugly looking directory names.

wmake/rules/linux64Nvidia/c

@@ -0,0 +1,12 @@
+include $(GENERAL_RULES)/Nvidia/c
+
+cARCH       = -m64
+
+# Compile option is non-mandatory, but must be non-empty
+sinclude $(DEFAULT_RULES)/c$(WM_COMPILE_OPTION)
+
+cFLAGS      = $(cARCH) $(GFLAGS) $(cWARN) $(cOPT) $(cDBUG) $(LIB_HEADER_DIRS) -fPIC
+
+ctoo        = $(WM_SCHEDULER) $(cc) $(cFLAGS) -c $< -o $@
+
+include $(GENERAL_RULES)/Nvidia/link-c

wmake/rules/linux64Nvidia/c++

@@ -0,0 +1,14 @@
+include $(GENERAL_RULES)/Nvidia/c++
+
+c++ARCH     = -m64
+
+include $(DEFAULT_RULES)/c++$(WM_COMPILE_OPTION)
+
+c++FLAGS    = $(c++ARCH) $(GFLAGS) $(c++WARN) $(c++OPT) $(c++DBUG) $(ptFLAGS) $(LIB_HEADER_DIRS) -fPIC
+
+Ctoo        = $(WM_SCHEDULER) $(CC) $(c++FLAGS) -c $< -o $@
+cxxtoo      = $(Ctoo)
+cctoo       = $(Ctoo)
+cpptoo      = $(Ctoo)
+
+include $(GENERAL_RULES)/Nvidia/link-c++

wmake/rules/linux64Nvidia/c++Debug

@@ -0,0 +1,2 @@
+c++DBUG     = -g -DFULLDEBUG
+c++OPT      = -O0

wmake/rules/linux64Nvidia/c++Opt

@@ -0,0 +1,2 @@
+c++DBUG     =
+c++OPT      = -O3

wmake/rules/linux64Nvidia/c++Prof

@@ -0,0 +1,2 @@
+c++DBUG    = -pg
+c++OPT     = -O2

wmake/rules/linux64Nvidia/cDebug

@@ -0,0 +1,2 @@
+cDBUG       = -g -DFULLDEBUG
+cOPT        = -O0

wmake/rules/linux64Nvidia/cOpt

@@ -0,0 +1,2 @@
+cDBUG       =
+cOPT        = -O3

wmake/rules/linux64Nvidia/cProf

@@ -0,0 +1,2 @@
+cDBUG       = -pg
+cOPT        = -O2

wmake/rules/linux64Nvidia/general

@@ -0,0 +1,13 @@
+CPP        = cpp -traditional-cpp $(GFLAGS)
+
+include $(GENERAL_RULES)/standard
+## include $(GENERAL_RULES)/Pgi/openmp
+
+ifneq (,$(findstring ~openmp,$(WM_COMPILE_CONTROL)))
+    include $(GENERAL_RULES)/no-openmp
+endif
+
+include $(DEFAULT_RULES)/c
+include $(DEFAULT_RULES)/c++
+
+# -----------------------------------------------------------------------------

wmake/rules/linux64Nvidia/mplibOPENMPI

@@ -0,0 +1,3 @@
+PFLAGS     = -DMPICH_SKIP_MPICXX -DOMPI_SKIP_MPICXX
+PINC       = -I$(MPI_ARCH_PATH)/include
+PLIBS      = -L$(MPI_ARCH_PATH)/lib$(WM_COMPILER_LIB_ARCH) -L$(MPI_ARCH_PATH)/lib -lmpi