diff --git a/mpich-aclocal_cc-implicit-int.patch b/mpich-aclocal_cc-implicit-int.patch
new file mode 100644
index 0000000..2f6ec43
--- /dev/null
+++ b/mpich-aclocal_cc-implicit-int.patch
@@ -0,0 +1,163 @@
+aclocal_cc.m4: Remove use of implicit int from weak symbol checks
+
+Implicit int is no longer part of the C language since the 1999
+revision.
+
+Submitted upstream: <https://github.com/pmodels/mpich/pull/6301>
+
+diff --git a/confdb/aclocal_cc.m4 b/confdb/aclocal_cc.m4
+index 36b44216d36dd8db..cafb5a6ae137f750 100644
+--- a/confdb/aclocal_cc.m4
++++ b/confdb/aclocal_cc.m4
+@@ -388,7 +388,7 @@ AC_CACHE_CHECK([for multiple weak symbol support], pac_cv_prog_c_multiple_weak_s
+         #pragma weak PFoo_ = Foo
+         #pragma weak pfoo_ = Foo
+         int Foo(int);
+-        int Foo(a) { return a; }
++        int Foo(int a) { return a; }
+     ]])],[AC_LANG_SOURCE([[
+         extern int PFoo(int), PFoo_(int), pfoo_(int);
+         int main() {
+diff --git a/modules/json-c/autoconf-archive/m4/aclocal_cc.m4 b/modules/json-c/autoconf-archive/m4/aclocal_cc.m4
+index 8a1552d561306f24..cd28a4f937eaf824 100644
+--- a/modules/json-c/autoconf-archive/m4/aclocal_cc.m4
++++ b/modules/json-c/autoconf-archive/m4/aclocal_cc.m4
+@@ -383,7 +383,7 @@ extern int pfoo_(int);
+ #pragma weak PFoo_ = Foo
+ #pragma weak pfoo_ = Foo
+ int Foo(int);
+-int Foo(a) { return a; }
++int Foo(int a) { return a; }
+     ])
+ ],[
+     AC_LANG_SOURCE([
+diff --git a/modules/yaksa/m4/aclocal_cc.m4 b/modules/yaksa/m4/aclocal_cc.m4
+index d15d6741602daf07..9fcf48527653ff01 100644
+--- a/modules/yaksa/m4/aclocal_cc.m4
++++ b/modules/yaksa/m4/aclocal_cc.m4
+@@ -422,7 +422,7 @@ extern int pfoo_(int);
+ #pragma weak PFoo_ = Foo
+ #pragma weak pfoo_ = Foo
+ int Foo(int);
+-int Foo(a) { return a; }
++int Foo(int a) { return a; }
+     ])
+ ],[
+     AC_LANG_SOURCE([
+diff --git a/src/mpi/romio/confdb/aclocal_cc.m4 b/src/mpi/romio/confdb/aclocal_cc.m4
+index 36b44216d36dd8db..cafb5a6ae137f750 100644
+--- a/src/mpi/romio/confdb/aclocal_cc.m4
++++ b/src/mpi/romio/confdb/aclocal_cc.m4
+@@ -388,7 +388,7 @@ AC_CACHE_CHECK([for multiple weak symbol support], pac_cv_prog_c_multiple_weak_s
+         #pragma weak PFoo_ = Foo
+         #pragma weak pfoo_ = Foo
+         int Foo(int);
+-        int Foo(a) { return a; }
++        int Foo(int a) { return a; }
+     ]])],[AC_LANG_SOURCE([[
+         extern int PFoo(int), PFoo_(int), pfoo_(int);
+         int main() {
+diff --git a/src/mpi/romio/mpl/confdb/aclocal_cc.m4 b/src/mpi/romio/mpl/confdb/aclocal_cc.m4
+index 36b44216d36dd8db..cafb5a6ae137f750 100644
+--- a/src/mpi/romio/mpl/confdb/aclocal_cc.m4
++++ b/src/mpi/romio/mpl/confdb/aclocal_cc.m4
+@@ -388,7 +388,7 @@ AC_CACHE_CHECK([for multiple weak symbol support], pac_cv_prog_c_multiple_weak_s
+         #pragma weak PFoo_ = Foo
+         #pragma weak pfoo_ = Foo
+         int Foo(int);
+-        int Foo(a) { return a; }
++        int Foo(int a) { return a; }
+     ]])],[AC_LANG_SOURCE([[
+         extern int PFoo(int), PFoo_(int), pfoo_(int);
+         int main() {
+diff --git a/src/mpl/confdb/aclocal_cc.m4 b/src/mpl/confdb/aclocal_cc.m4
+index 36b44216d36dd8db..cafb5a6ae137f750 100644
+--- a/src/mpl/confdb/aclocal_cc.m4
++++ b/src/mpl/confdb/aclocal_cc.m4
+@@ -388,7 +388,7 @@ AC_CACHE_CHECK([for multiple weak symbol support], pac_cv_prog_c_multiple_weak_s
+         #pragma weak PFoo_ = Foo
+         #pragma weak pfoo_ = Foo
+         int Foo(int);
+-        int Foo(a) { return a; }
++        int Foo(int a) { return a; }
+     ]])],[AC_LANG_SOURCE([[
+         extern int PFoo(int), PFoo_(int), pfoo_(int);
+         int main() {
+diff --git a/src/pm/hydra/confdb/aclocal_cc.m4 b/src/pm/hydra/confdb/aclocal_cc.m4
+index 36b44216d36dd8db..cafb5a6ae137f750 100644
+--- a/src/pm/hydra/confdb/aclocal_cc.m4
++++ b/src/pm/hydra/confdb/aclocal_cc.m4
+@@ -388,7 +388,7 @@ AC_CACHE_CHECK([for multiple weak symbol support], pac_cv_prog_c_multiple_weak_s
+         #pragma weak PFoo_ = Foo
+         #pragma weak pfoo_ = Foo
+         int Foo(int);
+-        int Foo(a) { return a; }
++        int Foo(int a) { return a; }
+     ]])],[AC_LANG_SOURCE([[
+         extern int PFoo(int), PFoo_(int), pfoo_(int);
+         int main() {
+diff --git a/src/pm/hydra/mpl/confdb/aclocal_cc.m4 b/src/pm/hydra/mpl/confdb/aclocal_cc.m4
+index 36b44216d36dd8db..cafb5a6ae137f750 100644
+--- a/src/pm/hydra/mpl/confdb/aclocal_cc.m4
++++ b/src/pm/hydra/mpl/confdb/aclocal_cc.m4
+@@ -388,7 +388,7 @@ AC_CACHE_CHECK([for multiple weak symbol support], pac_cv_prog_c_multiple_weak_s
+         #pragma weak PFoo_ = Foo
+         #pragma weak pfoo_ = Foo
+         int Foo(int);
+-        int Foo(a) { return a; }
++        int Foo(int a) { return a; }
+     ]])],[AC_LANG_SOURCE([[
+         extern int PFoo(int), PFoo_(int), pfoo_(int);
+         int main() {
+diff --git a/src/pm/hydra2/confdb/aclocal_cc.m4 b/src/pm/hydra2/confdb/aclocal_cc.m4
+index 36b44216d36dd8db..cafb5a6ae137f750 100644
+--- a/src/pm/hydra2/confdb/aclocal_cc.m4
++++ b/src/pm/hydra2/confdb/aclocal_cc.m4
+@@ -388,7 +388,7 @@ AC_CACHE_CHECK([for multiple weak symbol support], pac_cv_prog_c_multiple_weak_s
+         #pragma weak PFoo_ = Foo
+         #pragma weak pfoo_ = Foo
+         int Foo(int);
+-        int Foo(a) { return a; }
++        int Foo(int a) { return a; }
+     ]])],[AC_LANG_SOURCE([[
+         extern int PFoo(int), PFoo_(int), pfoo_(int);
+         int main() {
+diff --git a/src/pm/hydra2/mpl/confdb/aclocal_cc.m4 b/src/pm/hydra2/mpl/confdb/aclocal_cc.m4
+index 36b44216d36dd8db..cafb5a6ae137f750 100644
+--- a/src/pm/hydra2/mpl/confdb/aclocal_cc.m4
++++ b/src/pm/hydra2/mpl/confdb/aclocal_cc.m4
+@@ -388,7 +388,7 @@ AC_CACHE_CHECK([for multiple weak symbol support], pac_cv_prog_c_multiple_weak_s
+         #pragma weak PFoo_ = Foo
+         #pragma weak pfoo_ = Foo
+         int Foo(int);
+-        int Foo(a) { return a; }
++        int Foo(int a) { return a; }
+     ]])],[AC_LANG_SOURCE([[
+         extern int PFoo(int), PFoo_(int), pfoo_(int);
+         int main() {
+diff --git a/test/mpi/confdb/aclocal_cc.m4 b/test/mpi/confdb/aclocal_cc.m4
+index 36b44216d36dd8db..cafb5a6ae137f750 100644
+--- a/test/mpi/confdb/aclocal_cc.m4
++++ b/test/mpi/confdb/aclocal_cc.m4
+@@ -388,7 +388,7 @@ AC_CACHE_CHECK([for multiple weak symbol support], pac_cv_prog_c_multiple_weak_s
+         #pragma weak PFoo_ = Foo
+         #pragma weak pfoo_ = Foo
+         int Foo(int);
+-        int Foo(a) { return a; }
++        int Foo(int a) { return a; }
+     ]])],[AC_LANG_SOURCE([[
+         extern int PFoo(int), PFoo_(int), pfoo_(int);
+         int main() {
+diff --git a/test/mpi/dtpools/confdb/aclocal_cc.m4 b/test/mpi/dtpools/confdb/aclocal_cc.m4
+index 36b44216d36dd8db..cafb5a6ae137f750 100644
+--- a/test/mpi/dtpools/confdb/aclocal_cc.m4
++++ b/test/mpi/dtpools/confdb/aclocal_cc.m4
+@@ -388,7 +388,7 @@ AC_CACHE_CHECK([for multiple weak symbol support], pac_cv_prog_c_multiple_weak_s
+         #pragma weak PFoo_ = Foo
+         #pragma weak pfoo_ = Foo
+         int Foo(int);
+-        int Foo(a) { return a; }
++        int Foo(int a) { return a; }
+     ]])],[AC_LANG_SOURCE([[
+         extern int PFoo(int), PFoo_(int), pfoo_(int);
+         int main() {
diff --git a/mpich-configure-max_align_t.patch b/mpich-configure-max_align_t.patch
new file mode 100644
index 0000000..bc20d05
--- /dev/null
+++ b/mpich-configure-max_align_t.patch
@@ -0,0 +1,18 @@
+Remove spurious argument to AC_CHECK_ALIGNOF, which caused this
+configure test to fail.
+
+Submitted upstream: <https://github.com/pmodels/mpich/pull/6302>
+
+diff --git a/configure.ac b/configure.ac
+index 3e2aa2cb7e828675..f76eb49833bb358c 100644
+--- a/configure.ac
++++ b/configure.ac
+@@ -2701,7 +2701,7 @@ if test "$MPID_NO_FLOAT16" != "yes" ; then
+ fi
+ 
+ # ----------------------------------------------------------------------------
+-AC_CHECK_ALIGNOF([max_align_t],[0],[#include <stddef.h>])
++AC_CHECK_ALIGNOF([max_align_t],[#include <stddef.h>])
+ 
+ if test "$ac_cv_alignof_max_align_t" != "0" ; then
+     AC_DEFINE_UNQUOTED(MAX_ALIGNMENT,$ac_cv_alignof_max_align_t,[Controls byte alignment of structures (for aligning allocated structures)])
diff --git a/mpich-json-configure-__thread.patch b/mpich-json-configure-__thread.patch
new file mode 100644
index 0000000..2959ae8
--- /dev/null
+++ b/mpich-json-configure-__thread.patch
@@ -0,0 +1,17 @@
+Do not call undeclared exit function in __thread support check
+
+Submitted upstream: <https://github.com/pmodels/json-c/pull/2>
+
+diff --git a/modules/json-c/configure.ac b/modules/json-c/configure.ac
+index 9eb80bcf1c1d2e62..1511d7def23e8c39 100644
+--- a/modules/json-c/configure.ac
++++ b/modules/json-c/configure.ac
+@@ -69,7 +69,7 @@ AC_CACHE_CHECK([for __thread support], ac_cv___thread, [dnl
+ AC_LINK_IFELSE([dnl
+ AC_LANG_PROGRAM([[#undef __thread
+ static __thread int a; int foo (int b) { return a + b; }]],
+-		[[exit (foo (0));]])],
++		[[return foo (0);]])],
+ 	       ac_cv___thread=yes, ac_cv___thread=no)
+ ])
+ AS_IF([test "x$ac_cv___thread" != xno],
diff --git a/mpich.spec b/mpich.spec
index 0e5ff89..bab838a 100644
--- a/mpich.spec
+++ b/mpich.spec
@@ -16,6 +16,10 @@ Patch:          0003-Drop-build-flags-e.g.-specs.-and-lto-from-mpi-wrappe.patch
 Patch:          0004-Make-mpich.module-useful.patch
 # TODO: submit ^ upstream
 
+Patch:          mpich-configure-max_align_t.patch
+Patch:          mpich-aclocal_cc-implicit-int.patch
+Patch:          mpich-json-configure-__thread.patch
+
 BuildRequires:  make
 BuildRequires:  autoconf
 BuildRequires:  automake