CMake: support "make programs"

Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
diff --git a/programs/random/CMakeLists.txt b/programs/random/CMakeLists.txt
index 5940395..f0c7825 100644
--- a/programs/random/CMakeLists.txt
+++ b/programs/random/CMakeLists.txt
@@ -2,6 +2,7 @@
     gen_entropy
     gen_random_ctr_drbg
 )
+add_dependencies(${programs_target} ${executables})
 
 foreach(exe IN LISTS executables)
     add_executable(${exe} ${exe}.c $<TARGET_OBJECTS:mbedtls_test>)