https://savannah.gnu.org/bugs/?42973
https://bugs.gentoo.org/519552

these files use frexp/ldexp which is in -lm

--- a/Makefile.am
+++ b/Makefile.am
@@ -26,6 +26,7 @@ accton_SOURCES = accton.c common.c
 
 dump_acct_SOURCES = dump-acct.c common.c file_rd.c \
   pacct_rd.c
+dump_acct_LDADD = $(LDADD) -lm
 
 dump_utmp_SOURCES = dump-utmp.c common.c file_rd.c \
   utmp_rd.c
@@ -37,9 +38,11 @@ last_SOURCES = last.c common.c file_rd.c hashtab.c \
 
 lastcomm_SOURCES = lastcomm.c common.c dev_hash.c file_rd.c \
   hashtab.c pacct_rd.c uid_hash.c
+lastcomm_LDADD = $(LDADD) -lm
 
 sa_SOURCES = sa.c common.c file_rd.c hashtab.c \
   pacct_rd.c uid_hash.c
+sa_LDADD = $(LDADD) -lm
 
 noinst_HEADERS = common.h config.h dev_hash.h file_rd.h hashtab.h \
   pacct_rd.h uid_hash.h utmp_rd.h al_share.cpp linux-acct.h