fix compile errors for sev_server + sev_repair

sev/exe/sev_repair/src/os_templ/link_rule.mk

 ifndef link_rule_mk
 link_rule_mk := 1
 
-link = $(ldxx) $(elinkflags) $(domap) -o $(export_exe) \
+ifeq ($(PWRE_CONF_LIBHDF5),1)
+  ldsev = mpic++
+else
+  ldsev = $(ldxx)
+endif
+
+link = $(ldsev) $(elinkflags) $(domap) -o $(export_exe) \
 	$(export_obj) $(objects) $(wb_msg_eobjs) $(rt_msg_eobjs) \
 	$(pwr_eobj)/rt_io_user.o \
         $(pwre_conf_libdir) $(pwre_conf_libpwrsev) $(pwre_conf_libpwrrt) $(pwre_conf_lib)

sev/lib/sev/src/sev_dbhdf5.cpp

@@ -47,6 +47,10 @@
 #include "rt_errh.h"
 #include "co_dcli_msg.h"
 
+#include <cmath>
+
+using namespace std;
+
 #define ITER_MAX 50
 #define cName_Dir "/Dir"
 #define cName_Stat "/Stat"