[11:43:28 pluc@pluc ~/Desktop/Transmission-0.70]$ ./configure --verbose
System:  Linux
cc_test
cc -o testconf testconf.c
OpenSSL: openssl_test
cc -o testconf testconf.c -lcrypto
yes
GTK+:    gtk_test
pkg-config gtk+-2.0
no

*** GTK+ was not found, transmission-gtk will *NOT* be built. If you
*** wish to use the graphical version of Transmission then you will
*** need to install GTK+ headers and libraries. Try using your
*** distribution's package management utility to find a package called
*** libgtk2.0-dev, gtk2-devel, or something similar; then install it
*** and re-run this script.
lm_test
cc -o testconf testconf.c
testconf.c: In function ‘main’:
testconf.c:3: warning: incompatible implicit declaration of built-in function ‘cos’
/tmp/ccIfTNax.o: In function `main':
testconf.c:(.text+0x1b): undefined reference to `cos'
collect2: ld returned 1 exit status
cc -o testconf testconf.c -lm
testconf.c: In function ‘main’:
testconf.c:3: warning: incompatible implicit declaration of built-in function ‘cos’
lrintf_test
cc -o testconf testconf.c -lm
testconf.c: In function ‘main’:
testconf.c:3: warning: incompatible implicit declaration of built-in function ‘lrintf’
./testconf

Now use GNU make to build Transmission.
It may be called 'make' or 'gmake' depending on your system.