devtools: Integrate ARCH_MIN_GLIBC_VER table into MAX_VERSIONS in symbol-check.py

The (ancient) versions specified here were deceptive. Entries older than
MAX_VERSIONS['GLIBC'], which is 2.17, are ignored here. So reorganize
the code to avoid confusion for other people reading this code.

contrib/devtools/symbol-check.py

@@ -41,7 +41,14 @@ import pixie
 #
 MAX_VERSIONS = {
 'GCC':       (4,8,0),
-'GLIBC':     (2,17),
+'GLIBC': {
+    pixie.EM_386:    (2,17),
+    pixie.EM_X86_64: (2,17),
+    pixie.EM_ARM:    (2,17),
+    pixie.EM_AARCH64:(2,17),
+    pixie.EM_PPC64:  (2,17),
+    pixie.EM_RISCV:  (2,27),
+},
 'LIBATOMIC': (1,0),
 'V':         (0,5,0),  # xkb (bitcoin-qt only)
 }
@@ -79,14 +86,6 @@ ELF_ALLOWED_LIBRARIES = {
 'libfreetype.so.6', # font parsing
 'libdl.so.2' # programming interface to dynamic linker
 }
-ARCH_MIN_GLIBC_VER = {
-pixie.EM_386:    (2,1),
-pixie.EM_X86_64: (2,2,5),
-pixie.EM_ARM:    (2,4),
-pixie.EM_AARCH64:(2,17),
-pixie.EM_PPC64:  (2,17),
-pixie.EM_RISCV:  (2,27)
-}
 
 MACHO_ALLOWED_LIBRARIES = {
 # bitcoind and bitcoin-qt
@@ -162,7 +161,10 @@ def check_version(max_versions, version, arch) -> bool:
     ver = tuple([int(x) for x in ver.split('.')])
     if not lib in max_versions:
         return False
-    return ver <= max_versions[lib] or lib == 'GLIBC' and ver <= ARCH_MIN_GLIBC_VER[arch]
+    if isinstance(max_versions[lib], tuple):
+        return ver <= max_versions[lib]
+    else:
+        return ver <= max_versions[lib][arch]
 
 def check_imported_symbols(filename) -> bool:
     elf = pixie.load(filename)