Switch Linux runners to Ubuntu 26.04 except for MIPS (#3703)

The i386 build ran on ubuntu-22.04, which is retired on April 17, 2027,
and ubuntu-24.04 lacks fmod and exp10 in the static i386 libm.

Build on ubuntu-26.04 for every architecture except MIPS, whose cross
toolchains Ubuntu 26.04 no longer ships, and move the decnum, oniguruma
and valgrind workflows too. Most release binaries are now built with
GCC 15 and glibc 2.43, and they remain statically linked.

.github/workflows/ci.yml

@@ -37,6 +37,8 @@ jobs:
             CC: aarch64-linux-gnu
           - arch: armel
             CC: arm-linux-gnueabi
+            # Ubuntu 26.04 has no crossbuild-essential-armel
+            packages: gcc-arm-linux-gnueabi libc6-dev-armel-cross
           - arch: armhf
             CC: arm-linux-gnueabihf
           - arch: i386
@@ -65,7 +67,8 @@ jobs:
             CC: riscv64-linux-gnu
           - arch: s390x
             CC: s390x-linux-gnu
-    runs-on: ${{ matrix.arch == 'i386' && 'ubuntu-22.04' || 'ubuntu-24.04' }}
+    # Ubuntu 26.04 no longer ships the MIPS cross toolchains.
+    runs-on: ${{ startsWith(matrix.arch, 'mips') && 'ubuntu-24.04' || 'ubuntu-26.04' }}
     env:
       AR: ${{ matrix.CC }}-ar
       CHOST: ${{ matrix.CC }}
@@ -81,7 +84,8 @@ jobs:
       - name: Install packages
         run: |
           sudo apt-get update
-          sudo apt-get install -y automake autoconf libtool crossbuild-essential-${{ matrix.arch }}
+          sudo apt-get install -y automake autoconf libtool \
+            ${{ matrix.packages || format('crossbuild-essential-{0}', matrix.arch) }}
       - name: Build
         run: |
           autoreconf -i
@@ -127,10 +131,10 @@ jobs:
           - arm64
         include:
           - arch: amd64
-            target: x86_64-apple-darwin
+            target: x86_64-apple-macos14
           - arch: arm64
-            target: arm64-apple-darwin
-    runs-on: macos-14
+            target: arm64-apple-macos14
+    runs-on: macos-15
     env:
       LDFLAGS: -dead_strip
       SUFFIX: macos-${{ matrix.arch }}
@@ -146,12 +150,12 @@ jobs:
           brew install autoconf automake libtool
       - name: Set CC
         run: |
-          echo "CC=clang -target ${{ matrix.target }}$(uname -r)" >> "$GITHUB_ENV"
+          echo "CC=clang -target ${{ matrix.target }}" >> "$GITHUB_ENV"
       - name: Build
         run: |
           autoreconf -i
           ./configure \
-            --host="${{ matrix.target }}$(uname -r)" \
+            --host="${{ matrix.target }}" \
             --disable-docs \
             --with-oniguruma=builtin \
             --disable-shared \

.github/workflows/decnum.yml

@@ -7,7 +7,7 @@ on:
 
 jobs:
   disabled:
-    runs-on: ubuntu-24.04
+    runs-on: ubuntu-26.04
     steps:
       - name: Clone repository
         uses: actions/checkout@v7

.github/workflows/oniguruma.yml

@@ -9,7 +9,7 @@ on:
 # we test other options for --with-oniguruma here.
 jobs:
   installed:
-    runs-on: ubuntu-24.04
+    runs-on: ubuntu-26.04
     steps:
       - name: Clone repository
         uses: actions/checkout@v7
@@ -42,7 +42,7 @@ jobs:
             tests/*.log
 
   disabled:
-    runs-on: ubuntu-24.04
+    runs-on: ubuntu-26.04
     steps:
       - name: Clone repository
         uses: actions/checkout@v7

.github/workflows/valgrind.yml

@@ -7,7 +7,7 @@ on:
 
 jobs:
   linux:
-    runs-on: ubuntu-24.04
+    runs-on: ubuntu-26.04
     steps:
       - name: Clone repository
         uses: actions/checkout@v7

src/builtin.c

@@ -106,6 +106,13 @@ jv binop_plus(jv a, jv b) {
   }
 }
 
+// drem is an obsolete alias of remainder, and is missing from the static
+// libm of some platforms (e.g. i386 glibc 2.43), so use remainder instead
+#ifdef HAVE_REMAINDER
+#define HAVE_DREM 1
+#define drem remainder
+#endif
+
 #ifdef __APPLE__
 // macOS has a bunch of libm deprecation warnings, so let's clean those up
 #ifdef HAVE_TGAMMA
@@ -116,10 +123,6 @@ jv binop_plus(jv a, jv b) {
 #define HAVE_EXP10
 #define exp10 __exp10
 #endif
-#ifdef HAVE_REMAINDER
-#define HAVE_DREM
-#define drem remainder
-#endif
 
 // We replace significand with our own, since there's not a rename-replacement
 #ifdef HAVE_FREXP
@@ -236,9 +239,9 @@ static jv f_ ## name(jq_state *jq, jv input) { \
 #undef LIBM_DD
 #undef LIBM_DA
 
+#undef drem
 #ifdef __APPLE__
 #undef gamma
-#undef drem
 #undef significand
 #undef exp10
 #endif