+Similarly, there is a @code{targetcm} variable for hooks that are
+specific to front ends for C-family languages, documented as ``C
+Target Hook''. This is declared in @file{c-family/c-target.h}, the
+initializer @code{TARGETCM_INITIALIZER} in
+@file{c-family/c-target-def.h}. If targets initialize @code{targetcm}
+themselves, they should set @code{target_has_targetcm=yes} in
+@file{config.gcc}; otherwise a default definition is used.
+
+Similarly, there is a @code{targetm_common} variable for hooks that
+are shared between the compiler driver and the compilers proper,
+documented as ``Common Target Hook''. This is declared in
+@file{common/common-target.h}, the initializer
+@code{TARGETM_COMMON_INITIALIZER} in
+@file{common/common-target-def.h}. If targets initialize
+@code{targetm_common} themselves, they should set
+@code{target_has_targetm_common=yes} in @file{config.gcc}; otherwise a
+default definition is used.
+