diff -Nru pocl-3.0/debian/changelog pocl-3.0/debian/changelog
--- pocl-3.0/debian/changelog	2022-06-21 18:47:34.000000000 +0000
+++ pocl-3.0/debian/changelog	2022-07-03 11:56:05.000000000 +0000
@@ -1,3 +1,13 @@
+pocl (3.0-4+rpi1) bookworm-staging; urgency=medium
+
+  [changes brought forward from 1.5-6+rpi1 by Peter Michael Green <plugwash@raspbian.org> at Sat, 26 Dec 2020 20:26:31 +0000]
+  * Update symbols file for raspbian.
+ 
+  [changes introduced in 3.0-4+rpi1 by Peter Michael Green]
+  * Mark another symbol that does not appear in Raspbian as optional.
+
+ -- Peter Michael Green <plugwash@raspbian.org>  Sun, 03 Jul 2022 11:56:05 +0000
+
 pocl (3.0-4) unstable; urgency=medium
 
   * Switch to llvm 13.  (Closes: #1001317)
diff -Nru pocl-3.0/debian/libpocl2.symbols pocl-3.0/debian/libpocl2.symbols
--- pocl-3.0/debian/libpocl2.symbols	2022-06-21 18:47:34.000000000 +0000
+++ pocl-3.0/debian/libpocl2.symbols	2022-07-03 11:56:05.000000000 +0000
@@ -64,9 +64,9 @@
  _ZTINSt8__detail15_BracketMatcherINSt7__cxx1112regex_traitsIcEELb1ELb0EEE@Base 3.0
  _ZTINSt8__detail15_BracketMatcherINSt7__cxx1112regex_traitsIcEELb1ELb1EEE@Base 3.0
  (arch=armel riscv64)_ZTISt11_Mutex_baseILN9__gnu_cxx12_Lock_policyE1EE@Base 0.10
- (arch=!armel !riscv64)_ZTISt11_Mutex_baseILN9__gnu_cxx12_Lock_policyE2EE@Base 0.10
+ (optional=notarmelnotriscvandprobabllynotraspbian)_ZTISt11_Mutex_baseILN9__gnu_cxx12_Lock_policyE2EE@Base 0.10
  (arch=armel riscv64)_ZTISt16_Sp_counted_baseILN9__gnu_cxx12_Lock_policyE1EE@Base 0.10
- (arch=!armel !riscv64)_ZTISt16_Sp_counted_baseILN9__gnu_cxx12_Lock_policyE2EE@Base 0.10
+ (optional=notarmelnotriscvandprobabllynotraspbian)_ZTISt16_Sp_counted_baseILN9__gnu_cxx12_Lock_policyE2EE@Base 0.10
  (arch=armel armhf)_ZTISt19_Sp_make_shared_tag@Base 0.10
  (arch=armel riscv64)_ZTSN9__gnu_cxx7__mutexE@Base 1.0
  _ZTSNSt8__detail11_AnyMatcherINSt7__cxx1112regex_traitsIcEELb0ELb0ELb0EEE@Base 3.0
@@ -86,12 +86,12 @@
  _ZTSNSt8__detail15_BracketMatcherINSt7__cxx1112regex_traitsIcEELb1ELb0EEE@Base 3.0
  _ZTSNSt8__detail15_BracketMatcherINSt7__cxx1112regex_traitsIcEELb1ELb1EEE@Base 3.0
  (arch=armel riscv64)_ZTSSt11_Mutex_baseILN9__gnu_cxx12_Lock_policyE1EE@Base 0.10
- (arch=!armel !riscv64)_ZTSSt11_Mutex_baseILN9__gnu_cxx12_Lock_policyE2EE@Base 0.10
+ (optional=notarmelnotriscvandprobabllynotraspbian)_ZTSSt11_Mutex_baseILN9__gnu_cxx12_Lock_policyE2EE@Base 0.10
  (arch=armel riscv64)_ZTSSt16_Sp_counted_baseILN9__gnu_cxx12_Lock_policyE1EE@Base 0.10
- (arch=!armel !riscv64)_ZTSSt16_Sp_counted_baseILN9__gnu_cxx12_Lock_policyE2EE@Base 0.10
+ (optional=notarmelnotriscvandprobabllynotraspbian)_ZTSSt16_Sp_counted_baseILN9__gnu_cxx12_Lock_policyE2EE@Base 0.10
  _ZTSSt19_Sp_make_shared_tag@Base 0.10
  (arch=armel riscv64)_ZTSSt23_Sp_counted_ptr_inplaceINSt8__detail4_NFAINSt7__cxx1112regex_traitsIcEEEESaIS5_ELN9__gnu_cxx12_Lock_policyE1EE@Base 3.0
- (arch=!armel !riscv64)_ZTSSt23_Sp_counted_ptr_inplaceINSt8__detail4_NFAINSt7__cxx1112regex_traitsIcEEEESaIS5_ELN9__gnu_cxx12_Lock_policyE2EE@Base 3.0
+ (optional=notarmelnotriscvandprobabllynotraspbian)_ZTSSt23_Sp_counted_ptr_inplaceINSt8__detail4_NFAINSt7__cxx1112regex_traitsIcEEEESaIS5_ELN9__gnu_cxx12_Lock_policyE2EE@Base 3.0
  (optional=templinst)_ZZNKSt7__cxx1112regex_traitsIcE16lookup_classnameIPKcEENS1_10_RegexMaskET_S6_bE12__classnames@Base 3.0
  (optional=templinst)_ZZNKSt7__cxx1112regex_traitsIcE18lookup_collatenameIPKcEENS_12basic_stringIcSt11char_traitsIcESaIcEEET_SA_E14__collatenames@Base 3.0
  (optional=templinst)_ZZNKSt8__detail11_AnyMatcherINSt7__cxx1112regex_traitsIcEELb0ELb0ELb0EEclEcE5__nul@Base 3.0