Sometimes gcc -o2 finds more, dave have a look:
gcc -I/var/lib/citadel -Wall -g -O2 -Wall -Wcast-qual -Wcast-align -Wstrict-prototypes -D_REENTRANT -pthread -I ./include/ -I. -I ./include/ -DHAVE_CONFIG_H -c context.c -o context.o
context.c: In function ‘RemoveContext’:
context.c:166: warning: implicit declaration of function ‘become_session’
context.c: At top level:
context.c:414: warning: conflicting types for ‘become_session’
context.c:166: warning: ‘become_session’ declared inline after being called
context.c:166: warning: previous implicit declaration of ‘become_session’ was here
