Fix use-after-free

Thanks to LebedevRI for spotting that in the clang output.
(cherry picked from commit 78fe76472c3701274cbb719dfd77127fe2a908ee)
opencl: in debug mode tell user dt was built without opencl support
(cherry picked from commit d5e4b1d8bba3a881fd7de4e3dffb0216859d22ac)
(cherry picked from commit ad011cb2a4cd1d0be5b75627f021e4441feaf0a8)
Don't allow going to DT_MODE_NONE with key accels
(cherry picked from commit cb462d6da08fd25350d55cd20672a970fb05a86a)
pfm: move fallback date/time initialization to exif reading time.

this way it'll be done on import, not on thumbnail loading time.
(cherry picked from commit 591b23109c60434255f4a9acb50ba401151ce688)
Fix switching to all available modes when some are missing

Problem was that we use the enum dt_ctl_gui_mode_t as an offset for the
modules list :/
(cherry picked from commit 89e4854a140866aed6223c044889d71aa24e0a66)
Pentax K20D fw version 1.04.0.11 wb presets
(cherry picked from commit 9fbdd11d007534c952566b62e017efb8341bae70)
Make sure the module name are unique.

Never generate the same module name (multi_name) as this is quite confusing
for users. To do so we just check that the generated module name is not
already used.
(cherry picked from commit 77d4a97d823633da455133e8471ffc02ff5e3c41)
noise profile: sony a580 by toalaber
(cherry picked from commit 3a8a6d04bd204a4705ea6512dea6c7028bd320ea)
noise profile: fuji x10 by rob
(cherry picked from commit b24affc50a58f41c5c7849c2b58b017cd34983ae)
libraw: additional data checks backported from 0.15.4 (from lexa)
(cherry picked from commit 76ed400e6bfa510bf6d6a37831c669702c572ce0)
fuji: delete FinePix to match color matrices data.

don't you just love fuji.
(cherry picked from commit 0a180faadd5d3b977b4776c1e4b78e90535b80cd)
add noise profile for the Pentax K20D
(cherry picked from commit f50fd29bc84a804516a5a33fa22983953c58b227)
avoid I/O deadlocks between DT and GDB in SIGSEGV handler
(cherry picked from commit 2f1a9a36f7d1bc00b82b2066e78898d170c425b6)
Merge branch 'darktable-1.2.x' of github.com:darktable-org/darktable into darktable-1.2.x